Linux was the first desktop to use 64-bit in 2001; but I wasn't using it then. When I switched to Linux about 5 or 6 years later I naturally just used 64-bit: I cannot believe anyone [ except legacy systems ] still uses 32-bit.
I've been hoping for 128-bit, lo, these many years
There's very little point in enabling an OS to handle an address spaces bigger than the native pointer size.
And that would require finding a use case for a 128-bit CPU that couldn't be fulfilled in a special-purpose processor like a DSP or GPU or through SSE instructions.
(As an aside increasing the pointer size slightly increases memory consumption because now all your pointer-sized data takes twice as much space)