But... but... it was just announced! Well aren't YOU full of rainbows and sunshine!

Seriously, though, given the fact that Apple means to invest heavily in their own architecture and that their strategy on that is long-term, any M1-based machine will be supported for a very, very long time.

Any subsequent chip series - M2, M3, M4 etc. - will be backwards compatible with the M1, just as the A15 is with e.g. the A8. Software of e.g. 2030 will run on the Mac Studio as intended, just slower than the more modern Macs of that time.

So I'd say that whoever buys a well-equipped Mac Studio now will use it with no trouble at all for six to seven years at the very least. There may come a time that Apple will release a macOS the M1 will not be able to fully support, but even then the machine itself will be perfectly usable.

Given how much of an overkill the Mac Studio is right now, I'd give it a decade before it is truly obsolete. More than enough time for a spectacular return on investment.