Macs have never been about highest possible performance at any price point. But there is a niche where people want a very fast computer that is quit and not too ugly (and who can find their apps on macOS).
Putting two GPUS in a tight spot and the limitations of the time basically doomed it to failure but now we have much better data rates and better iGPUs.
It's a valid approach in theory but it seems pretty clear that the market hasn't embraced it. The most recent Mac Pro recognized that people weren't embracing it, but really, are there many (or any?) 3P cards that can be plugged into a Mac Pro?
You can build/get quiet PCs too. Theres a whole PC accessory company called be quiet! even. And there's some very nice IMO cases that look better than the Mac Studio or Pro...
My comparison is up to date as the top end chips from Intel and AMD and the top-end Nvidia GPUs handily outpeform the top-end silicon in the Mac Studio's highest end configuration. And for a lower cost. The Studio is a solid machine, but it doesn't have the same 'this is about as good as you can get without a server farm' performance of the top-end Mac Pro when it launched.