What changed in the last year is that people want a lot more space which is pulling them out of the "expensive apartment" market and into the "house" market, while also being less concerned about commute distance. So the expensive apartments fall in demand while the houses go through the roof, without effecting the lower end of the rental market at all.
You forget all the horrible fees that come with owning a place (HOA, maintenance, property taxes, 6% lost to agents at every transaction)
My rent means that there are tens of thousands of dollars a year that I'll never be able to invest in anything. So even if I had a better investment option than taking a 5x (or more!) leverage multiplier on a downpayment, it would still have to overcome a pretty big disadvantage right there to come out ahead in the long run.