[rossdavidh]

1) technically, someone is fabricating semiconductors in their garage, but as regards the world economy your point is still valid: https://hackaday.com/2021/06/29/garage-semiconductor-fab-get...

2) the equipment used in older fabs, is in many cases not even made any more. It's much like why the vinyl record manufacturing took a decade or more to ramp back up when the demand for vinyl records began going up instead of down. Nobody was making that equipment any more. The older fabs don't use the same equipment as the new fabs, except less of it; they use quite different equipment, and in some cases newer equipment actually wouldn't be able to make the older chips. I don't work in semiconductors, but I did from 1989 to 2004, and worked on several cases of trying to move old processes into newer fabs. It's not easy or quick, and in some cases you have to move the old fabs' equipment into the new fab.