You can hire people from anywhere with the internet. Economics alone are likely to dictate that things move from centralization to decentralization.

$3m dollar homes, extremely high office rents, wasted energy and time on commuting, higher comp expenses, smaller hiring pool. Even if centralization/in-person is more efficient, likely not efficient to enough to overcome these economics.

The businesses that learn how to maneuver in a decentralized/online first manner have huge starting advantages over those that don't. Though, we will see in time.

It's possible the centralization gap will be much smaller in cities that choose to meet demand for housing/office/amenities.

That only really applies to work that can be efficiently done remotely. While a lot of software can, there's a significant chunk that cannot and never will be able to. As soon as you have situations where you need specialized hardware, remote work becomes really inefficient/untenable.

True, though many types of hardware work can still be distributed.

More than one phone prototype can be made and shipped to different branch offices, for example. Do you need the entire company working off one hardware prototype? Is that even a practical way to iterate? Not really. It's only the more bespoke/expensive hardware that is more difficult to distribute.

But software employment is currently much larger percentage of the IT workforce anyway