This is BS. The reason for the high home prices is the record low interest rates causing more demand from people who are currently paying high rents. Simple supply and demand.
Because of that rents are going down in many places especially the high rent districts. San Francisco rents are down almost 30%.
If interest rates start going up (and they will) the demand from buyers will decrease and prices will stabilize or drop.
The low interest rates are mainly due to the virus as both the fed and the government injectected trillions into the economy to keep it from crashing during the plague.
There is some truth to what you have said, however, and this is an anecdote, a very accomplished real estate agent told me recently companies from Asia, South America, Europe, Australia, North America, etc. are outbidding individual home buyers. He said he has never seen anything like it.
Now I would say they are doing this as a hedge against inflation, not a long-term investment. In many parts of the US one can lose money if you hold on to residential real estate for too long. In my city many neighborhoods can go south in 25 years or less. If one makes it to 50 years without houses losing value it is a miracle.
By the way rent is up 15% in my area just so far this year, so not all markets are down.