I think there are a number of good answers to this already, and they make some good points. But I think you are also asking a question that does not have a single answer and cannot be directly answered, and so you will at best get guidance to finding your own answer. To summarize some existing points and add to them, consider the following:
How are you choosing your degree?
I had an acquaintance who graduated with a BS from a 4 year college in something like Greek History. I met him because he worked for minimum wage in a business my parents had recently purchased. Another friend graduated from a 4 year college with a degree in mechanical engineering, and at that same time was working for Bayer for somewhere around $60k per year (in an area with a very low cost of living).
Whether you're choosing your degree based on high paying career prospects or just what interests you plays a large role in a cost benefit analysis. Unless you are independently wealthy, I recommend you always choose a career first, and let your choice of degree follow from that.
How much do you really need to spend?
I have two acquaintances who worked in college financial aid offices. They were specifically trained not to help students determine how much they need, but to help them determine how much they can get. In many cases a student could survive on a $100k loan, but they qualified for $150k. The FA office would encourage them to take the $150k, and then the students, having no experience in personal finances, would use the extra money as disposable income during their college life. In essence, this increased their cost of college by 50%.
Similarly, many students move away from home, as much as doubling their financial outlay for the degree. If you have the option of commuting from your parents' house, consider it and how it affects you financially.
Similarly, community colleges offer a great education in many areas for as much as 90% less than universities, and an Associates Degree will transfer to most universities. When you finish your BA no one will know or care that you spent your first two years at a CC; just that you achieved your BA from the university. Consider this as well.
So determining how much you actually need and financing that, as opposed to taking all that is recommended or offered, plays a large role in a cost benefit analysis.
Is financing really your only income source
Many students are surprised by just how much money is available via scholarships. Many are for academic or athletic achievement, but there are also many that are not. Consider which you may qualify for and which you may qualify for if you work towards that goal. If scholarships reduce your degree cost by 50%, that must be taken into your account in your cost benefit analysis.
Similarly, many students consider working and college to be mutually exclusive. For many, they need not be. All degrees differ in the study time required, as do all students. But many students can easily work a part time job during school. Assuming a pay rate of $10 / hour, and a a work schedule of 15 hours per week during school semesters (9 months of the year) and 40 hours per week during breaks, the student will have a annual gross income of $10,200, or $40,800 over the course of the four year degree. In other words, attending college does not always mean you need to sacrifice earning potential as an opportunity cost. Consider this in your cost benefit analysis.
Some further calculations and statistics
I think you may find some of the calculations and statistics I posted in my question at https://parenting.stackexchange.com/questions/28167/should-i-financially-assist-my-child-in-paying-for-college to be very useful.
What is value?
As has been mentioned, a degree, especially one from a university that provides a breadth of knowledge, is invaluable. Having the capacity to understand the world around you, understand the foundations of business and politics, and having a springboard for further study, can change your life in fundamental ways you cannot imagine. Not to mention the educational basis for any potential later life career switch.
Careers that require degrees also often include better benefits, more vacation time, paid sick leave, retirement contributions, increased scheduling flexibility, and other intangibles. Some jobs without degree requirements also include some of these, but many do not.
Consider that even if there is no economic value, a degree may still be worth many tens of thousands of dollars in the way it enriches your life.
Is this correct?
is Pete correct that 75K income for a potential degree (career path) is not enough to justify student loan debt?
No. This is absolutely incorrect, simply due to the fact that there are so very many variables involved. For instance, someone who finishes college with no debt due to scholarships and part time work can justify the degree even if their pay remains unchanged. Any answer that puts a simple number on such a complex question is flat out wrong.
I consider this especially egregious considering that where I live (low cost of living) an annual salary of $75k would be considered 'wealthy', and about double what the average individual earns.
Much of what has been presented is very "consider this", so some concrete steps to take to figure all this out may be in order. I would recommend you do this:
1) Determine the statistically average pay for the career you will likely end up in without a degree. This is easily found on Google.
2) Choose a career you may be interested in and look up the statistically average pay for that career.
3) Determine the degree and schooling you need to work in that career.
4) Determine the cost of that schooling. Take into account cost saving measures (commuting, community colleges, etc) and income opportunities (scholarships, part time work, etc) to minimize the cost. Use this formula to determine what you would need to borrow: (tuition + boarding + food + transportation) - ((part time job income - expenditures) + scholarships + savings).
5) Determine interest on the amount you would need to borrow and use this formula to determine total cost of schooling: borrowed amount + interest + income from work you would have done had you not gone to school
6) Now use this formula to determine the value of schooling: (annual salary of career - annual salary of uneducated career) * 50
7) Now use this formula to determine whether the degree is worthwhile: value of schooling - total cost of schooling. If the number is positive, your degree is worthwhile. Remember, this is a purely fiscal determination! It does not take into account comfort, happiness, or other intangibles.
8) Now determine if you can repay your loans in a reasonable amount of time. Use this formula: Repayment period = amount borrowed / (annual net salary of career - annual net salary of uneducated career). For this step you can estimate net pay as 75% of gross pay
Statistically speaking, if you are fiscally responsible, and choose a target career instead of choosing a degree, it should always be worthwhile.