Well no, actually. Good Nvidia cards are also nearly extinct, because they are actually still profitable for Ethereum mining. So when people couldn't find AMD cards, they settled for bying Nvidia.

Unlike the situation with Bitcoin a few years ago, Nvidia cards are ok for mining Ethereum (something like 40-50% lower hash rate than AMD, but still very much profitable).

That's true. The hashrate/$ and hashrate/watt for the AMD cards is much more favorable for Ether mining.