It's simple, the 395+ Max Strix Halo you bought for $1800 is now a ~$4000 build (at least the AMD AI dev unit). If only we had time travel right? Either way, the Nvidia unit comes with Connect-X 7. That may or may not matter to you, but the hardware for that isn't cheap. In general the Nvidia cards also have better support for models. I know AMD is trying to catch up but anything except their datacenter cards do not seem to be getting a lot of attention.