Ahh, most of the cost is RAM. Then GPU then CPU.

Look at a Dell or HP server configurator website to see why.

If you "only" need GPU, a craigslist search should find a less expensive 2 or 3yo server to plug your latest GPU into.

Ahh, most of the cost is CPU. It’s so expensive to have register memory, that you have l1 l2 caches. Each further away and cheaper. RAM is the cheapest which is why you can have so much of it. Try having 16G of register memory. UMA is a step towards that, but not quite.

Yes, so if your CPU doesnt need to be the size of a box of cards, your GPU doesnt need to be the size of a library book, the manufacturing costs would go down.

It gets harder to build big things with small transistors, not easier, due to yield.

Also if you want to use big transistors, power dissipation also means you have to stay small or you will start fires.