[mapt]

Mirror grinding is still a thing. Just not a thing that young people generally do. Distribution got easier and real estate got more scarce. Those of us who have garages, have filled them up.

In my understanding it's gotten considerably easier over the years with better availability of diamond and CBN abrasives, and with more electronic control of the grinding hardware. Slumping glass and bonding a thin sheet to ceramic foam reduced the costs and weight a great deal as well. Mastering these techniques make it easy to start a small business rather than to do a one-off in your garage, though.

As a sidenote: The Celestron RASA astrographs are so effective and so inexpensive of a wide-field instrument that it's a lot harder to justify the DIY activity that existed in the 2000's.

[chantepierre]

There is quite a vibrant community of young people grinding mirrors, it just has displaced to Discord. The "Observational astronomy" discord server has a lot of late-teenagers and young adults grinding. Our french Astro-FR server has people in their thirties grinding. But as you pointed out, garages are sparse and people seem to take shortcuts : finding bad pre-polished mirrors as blanks, slumping glass sheets to shape and continuing with fine grinding...