I think you are overly discounting time zone. Someone working remotely, but within 3 time zones, is much easier to collaborate with than someone 9-12 timezones away.
It's horrible for the people who have to work in such a system. We have people in India and during phases where you have to collaborate a lot, either the US people or the India people have to constantly work at night. And the company demands this in addition to regular working hours. We also have people in South america and that's much better to deal with because working hours overlap during the day.
I don't talk to the founder much, but when I do, it is clear they have no problems with remote talent (other than that they'd like to hire 1-2 more developers and are having a hard time finding them).
Sound familiar? It's surprising to hear this so early in the 'remote-first' trend. I think what we'll find is that actually, there is still a dearth of top software talent (even if you include hiring worldwide). It will probably depress wages some, but not as much as people think.
You’re right that it’s far, far harder to have teams built from members in opposite time zones. However, the people pushing for fully asynchronous work environments are building company dynamics that lend themselves to being timezone agnostic, so it can be done if you want it badly enough.
And that means the central time zone worker is joining it at 0630 and the west coast worker is joining at 0430