There's a 45% performance uplift between M2 Max and M3 Max in benchmarks.
You still get more performance between M2 Pro and M3 Pro. And you get significantly more if you're upgrading from M1 Pro.
The M3 Pro is a properly crippled M3 Max.
It's called market segmentation, and Apple is very good at it, but in the early days of M1 (and M2, which is just a warmed-over M1) they didn't have the engineering time to make 4 tiers (Base, Pro, Max, Ultra) and had to do a half-assed job of chopping off part of the Max to make the Pro. With M3, the Pro is its own design, with carefully designed limitations to force you to the Max.
Also, I see the discussion about pro vs max being focused on performance, but what about thermals or battery life? Perhaps many professional users would be better off using pro and not max?
That would be entirely dependent on whether they benefit from the extra performance or RAM that you can get with Max.
I don't think that there's a significant difference in thermals or battery life on identical workloads. My M2 Max gets me through a full working day with 30-50% charge still left. It's the only laptop I've ever had I can be completely confident about should I not bring a charger with me.