I doubt that. A RTX 3090 has 24 GB RAM. It is sought after for 3D rendering applications.
The big enterprise megacorps that build 3D rendering farms tend to only buy new hardware, even if the price-to-performance ratio sucks. The extra capital cost is tiny compared to the labor cost of six figure technicians & developers. These companies need warranty support as well. At worst, they will buy last-gen Quadros or RTX 4090's.
The ideal market for these used RTX 3090's would be somebody like Linus Tech Tips or a scrappy AI research startup who needs model training for cheap. These types of companies won't amount to enough demand to buy millions of RTX 3090's.
Therefore I'm sticking to my $500 prediction.
Consensus layer dev call wrapped up:
Thank you for the constant updates on the devs. I would award you merit but sadly I don't have enough.
The market for RTX3090 rendering would be DAZ3D. It provides amazing performance with IRAY. Go check out the DAZ3D site. People are spending tons of money to buy 3D characters, clothing, accessories etc. These people would love to get their hands on a RTX3090 because the 24GB RAM allows you to load more figures and props etc. and render with more textures. Essentially you can have bigger scenes with larger textures and render them with IRAY. I have used a 1080 TI with IRAY and unfortunately the 11GB RAM only goes so far. Then when you do the final render the 1080 TI sits idle while the CPU is rendering in IRAY and taking a lot of time compared to the 1080 TI.