You are correct that the manufacturing cost has gone up.
You are incorrect that this is the root cause of GPU prices being sky high.
If manufacturing cost was the root cause then it would be simply impossible to bring prices down without losing money.
The root cause of GPU prices being so high is lack of competition - AMD and Nvidia are choosing to maximise profit, and they are deliberately undersupplying the market to create scarcity and therefore prop up prices.
"AMD 'undershipping' chips to help prop prices up"
https://www.pcgamer.com/amd-undershipping-chips-to-help-prop...
"AMD is ‘undershipping’ chips to balance CPU, GPU supply Less supply to balance out demand—and keep prices high."
https://www.pcworld.com/article/1499957/amd-is-undershipping...
In summary, GPOU prices are ridiculously high because Nvidia and AMD are overpricing them because they believe this is what gamers will pay, NOT because manufacturing costs have forced prices to be high.
