As I understand it, the spike in housing prices is driven primarily by a huge inventory shortage. I'm not sure how COVID is causing the inventory shortage, but it's a real thing. I've also heard at least anecdotes of people leaving the big cities for the suburbs in the aftermath of the protests last summer. Maybe it's just a matter of businesses and employees hunkering down, rather than workers seeking new employment?
What's going to happen to housing prices? It's anybody's guess. If all the vaccines work and the pandemic fizzles out, then housing supply could increase as more people are comfortable moving. Or it might not, since more people can work from home. And we have a government pumping money into the economy, which could also be contributing to the price increases. The cost of building supplies has skyrocketed in the last year--lumber prices, in particular, have doubled in price. When I looked at fiberglass batts, they were 50% more expensive than they were a year ago.
IMO, yes, eventually prices will level out and maybe even drop a bit, as more supply comes online and the surge in demand for building supplies subsides. But if/when that happens is unknown.
As for the factors you mention, I agree with you on #4. #2 is possible, but the crash of 2007 is probably recent enough that (hopefully!) builders won't make the same mistakes again. #1 will happen eventually, but my guess is that it'll be a gradual process. But I could be totally wrong--positive COVID tests have dropped about 40% since their peak about two weeks ago, and hospitalizations are down about 25% over the same period, which is a rather remarkably fast change. As for #3, that really depends on where you are. If you're in a suburb of a major city outside of California, then I don't see that happening--with the opportunity to work remotely, living in the city loses a major selling point (i.e. proximity to work).