On Reddit there's reports of 8x4090, or even 8xH100. I don't know where people get this kind of money for this, and why they don't rent infra instead.
Edit: could also just be more-money-than-sense. Never discount stupidity.
The 4090 will likely maintain 50% of its current value due to its memory capacity over the next 12-18 months.
CapEx vs OpEx is a thing even if you are not a business…