Apple hasn't suddenly stopped being Apple. They strongly differentiate the boundaries of their product lines and have never let use case leakage spread across their product lines.

Yes, but the M3 was used in the Mac Studio as well as the Macbook Air, wasn't it?

The 128gb limitation feels like it's portrayed as a limitation of the M5 chip itself -- not just of the Macbook Air product line.

Only the m3 ultra supported more than 128gb, I don't think they used them on anything other than the studio.