Most of the consumer products that you buy at retail these days are commodity priced, and have been for a long time. Margins are thin, so if there are retail salespeople milling about, their compensation isn't coming from the TV or computer with a 6% gross margin.
It comes from the extended warranty programs (which are not insurance and do not have regulated underwriting standards), which are typically sold at a 65-95% gross margin. So that $200 warranty most likely costs the retailer $50. The salesman gets $15-25. I paid for my college education working at a CompUSA selling these things, along with other high margin items that paid commission.
In most cases, you aren't getting much coverage anyway. Most products carry a 1 year warranty, and using most "gold" or "platinum" credit cards doubles a manufacturer's warranty by up to 1 year. So with most transactions, you are already walking away with a 2 year warranty.
Warranties or service plans make sense for durable goods that cost alot and are expected to last a long time and/or require regular maintenance. I think they especially make sense if your budget is really tight -- a fixed maintenance cost can be an asset to some people because they can plan around it. Examples of this include: service plans for a furnace, boiler or water heater or a car if you're buying a manufacturer-endorsed service/maintenance plan from a dealer.