I am not a pro musician since I don't generate money from it.
I am a professional in another field, but the macs I use for music making.
I am not a professional, but I don't want a toy machine,
but right now, unlike in windows world, you either get a mac mini and Frankenstein it up,
or get an iMac, which in my case don't work since I already have a nice 4k monitor...
so no options for the dreamers like me,
I dream to someday live from my music,
but I have a family to feed so I work as an engineer.
In the meantime,
I cannot justify buying a computer that starts at 6,000 just to follow my dream...
So yes, if you are a professional that requires a mac pro, and it will pay itself with that work, good for you!
BUT, remember when you started,
and remember that someone younger is starting right now.
You can bet your mac pro that some of those upcoming pros would be 10x better at whatever you do,
and I bet you they are making all they can with as little as they have, that is how life works!