You forgot the biggest one – cheap mortgages backed by unlimited money printing. Ever since 2008 loading up on as much <3% housing debt as you can afford has been a no-brainer investing strategy.
Of the two additional properties I own, marked as investment and vacation, they are 3.5% and 3%, refinanced, and bought during the pandemic. The former, five years prior, was marked as non warrantable, as in no bank would even give a loan for it.
So, while investors don’t get the same rates as homeowners, they still got very good rates. If I had had capital, I would have bought a dozen more units at that time.
This is what I find concerning though, we're now seeing the damage of the endless money printing, through inflation.
Inflation causes living costs to go up, which means people have less money for rent, which means people who have borrowed to service mortgages don't get money, which has a knock on effect...meltdown.
Edit: Will guess I got a downvote for using the world meltdown, which was almost sarcasm because the powers that be will never let this happen.