I'd add a point (3) to that, which is that there are still a ton of tech companies which never had a snowball's chance in Death Valley of making it, but which went public anyway because during the mania just about ANYTHING could get venture capital, and just about ANYTHING that could get venture capital could have a blockbuster IPO.
Many of these non-business businesses are still burning their IPO cash and will continue to fail in waves as that cash runs out. Their lingering existence probably has both good and bad aspects to it. On the one hand, for so long as they linger they are a source of jobs, (however tenuous), in a business sector (and geographic region) badly in need of them. On the other hand, the cash they are living off of could be put to better use elsewhere.