This was always part of the original design of the Mac Studio so they have never changed the design. This is a spec bump.

I have an old style M1 Mac Mini on my desk and I could probably count on one hand the number of times I had to hit the power button, and Apple knows this, so they decided it wasn’t worth the machining cost to drill a hole in the back of the top shell and engineer a power button to the tolerances you’d expect.

Imagine, my Apple TV doesn’t even have a power button! My MacBook tells at me if I accidentally press it when doing a TouchID!

Power buttons are for power users. lol