https://www.reddit.com/r/Doom/comments/8a1m9s/psa_deactivate...
Problem for id is that you have no sane way of profiling the DOS port on NeXT.
I did game engine dev professionally in 1994 (and non-professionally before that). We profiled both time and memory use, using GCC and gprof for function-level profiling, recording memory allocation statistics by type and pool (and measuring allocation time), microbenchmarking the time spent sending commands to blitters and coprocessors, visually measuring the time in different phases of the frame rendering loop to 10-100 microsecond granularity by toggling border or palette registers, measuring time spent sorting display lists, time in collision detection, etc.
You might regard most of those as not what you mean by profiling, but the GCC/gprof stuff certainly counts, as it provides a detailed profile after a run, showing hot functions and call stacks to investigate.
It's true that most of the time, we just changed the code, ran the game again and just looked at the frame rate or even just how fluid it felt, though :-)
I'm guessing they used gcc on NeXT but profiling that platform probably didn't make much sense, different compiler, different CPU, different OS...
The game was written on a TurboColor which had a Motorola 68030 (?) that ran at 33MHz and supposedly only ran at 15FPS (probably as slow as a 386DX/33 at the time)
While 486 AGI stalls were trivial, especially Pentium changed the game with its U and V pipes. You could no longer trivially eyeball what code is faster. Profiling was a must.
Heck, I even "profiled" my C64 routines in the eighties by changing the border color. You could clearly visually see how long your code takes to execute.