So how are folks doing "Classic Mac" development these days?

Was this done on real hardware? Are folks developing within simulators? Just curious what the Classic development experience is like today.

Sometimes I muse it might be fun to dabble, but then I look at that 9" screen and go "Um, nah."

For example, many folks do CP/M development, but almost none of them do it actually on a CP/M machine. I think that's similar for many retro projects.

If you can live with cross-compiling from a modern PC (or Mac) you can use https://github.com/autc04/Retro68 which uses a recent version of GCC.