Home prices peaked in 2007 and then started to decline because of the 2008 Global Financial Crisis. In 2008 the Fed began Quantitative Easing. Median home value lost about 30% of their value over the next 3 years and it took another 6-7 years to surpass the 2007 high.
That period demonstrates that it's not true that:
When the government starts to do "quantitative easing" or print money, then the price of a house can go from $1.2 million to $1.5 million easily, or to $1.8 million after 2, 3 years. That's because money has shrunken in value.
Not even close to the truth. Home prices climb because Quantitative Easing involves the Fed purchasing longer-term securities in order to increase the money supply. This lowers interest rates which encourages lending, investment and home buying demand.
And if it is cash we are holding, it shrinks in value. But now, when a beef noodle changes from $7 to $12, now your $1000 changes to $2000 or $3000. (leveraged), so now the 50% price increase in beef noodle seems like a mickey mouse to you.
This is another fantabulous exaggeration. Beef noodles (and other consumer products) have never increased 40% during periods of Quantitative Easing. In the past 35 years, inflation has barely topped 5% three times. When QE began in 2008, we had deflation for two years - consumer prices declined.
Regarding your statement that:
So if we put 20% down, i.e., $240k to buy a $1.2 million house, and it goes up to $1.5 million within a year, we have just doubled our money from $240k to extra $300k equity (the gain).
Apart from these fallacies, you have failed to take into account possible initial repairs, mortgage interest, taxes, insurance, maintenance, and unexpected repairs. Add utilities to that list if the house isn't rented.
Your conclusion that it's a no-brainer that "When the government starts to do "quantitative easing" or print money, then the price of a house can go from $1.2 million to $1.5 million easily, or to $1.8 million after 2, 3 years" is factually incorrect.