I just spec'd out a HP Z6 to the min spec of the Mac Pro - it came to about $4000 (and that is EU prices, I am sure the US prices are less) - so 20% difference.
An maxed out z8 is $50k - but that is way over what most people need, or you can do with a Mac Pro
If you look at other manafacturers - you can get insane performance for much cheaper.
2 x AMD Epycs (64 cores per CPU, 128 cores / 256 threads in the box)
1TB RAM
2x2TB SSD
2 x Quadro RTX 6000
Is $38,000. It is not even in the same sport, let alone league as the mac pro
An maxed out z8 is $50k - but that is way over what most people need, or you can do with a Mac Pro
If you look at other manafacturers - you can get insane performance for much cheaper.
2 x AMD Epycs (64 cores per CPU, 128 cores / 256 threads in the box) 1TB RAM 2x2TB SSD 2 x Quadro RTX 6000
Is $38,000. It is not even in the same sport, let alone league as the mac pro