[perardi]

I think the end of support for 32-bit applications in 2019 helped, slightly, with the run-up.

Assuming you weren’t already shipping 64-bit applications…which would be weird…updating the application probably required getting everything into a contemporary version of Xcode, cleaning out the cruft, and getting it compiling nice and cleanly. After that, the ARM transition was kind of a “it just works” scenario.

Now, I’m sure Adobe and other high-performance application developers had to do some architecture-specific tweaks, but, gotta think Apple clued them in ahead of time as to what was coming.