Not technically true. The Mac Pro 2023 has 6 PCI slots...

... for an eye watering $3,000 over the exact same spec Mac Studio.

I liked my cheesegrater, though I didn't like the heat output.

And I cannot justify that. I sacrificed half the throughput (2800MBps) for $379 and got an external 4 x M.2 TB3 enclosure.

Oh, and a USB 3 hub to replace one I had installed in the cheesegrater to augment the built in ports. $400 give or take.