That data is not definitive; it is indicative of use, yes, but the only relevancy is new sales. Besides, not everyone is opting into Steam for data collection.
The GPU mining segment isn't dead; it is stalled for an uncertain amount of time due to market conditions, and it is not if 'Gaming' PCs have stopped mining either. Those hashrates which was allegedly obliterated by the ETH merge are coming from somewhere and there are loads and loads of single GPUs (by hashrate estimates) running on pools. This is besides the point, if the RTX 4000 series is profitable at any point during its lifecycle it will be bought up. Scalping will continue regardless, but with a larger supply volume retail would be more accessible.
Which brings me to the street price. For those who weren't early paid almost double the price for those GPUs.
The Verge had a good break down,
How much are the PS5, Xbox Series X, RTX 3080 and RX 6800 actually worth?
www.theverge.com
Nvidia RTX 3090 (MSRP $1,499 / Street price $2,076)
Nvidia RTX 3080 (MSRP $699 / Street price $1,227)
Nvidia RTX 3070 (MSRP $499 / Street price $819)
Nvidia RTX 3060 Ti (MSRP $399 / Street price $675)
AMD RX 6800 XT (MSRP $649 / Street price $1,232)
AMD RX 6800 (MSRP $579 / Street price $841)
as much as there are disgruntled consumers, most whom are not in the target market of the 4090, the 4090 will be more affordable than the 3090. The same will apply to the 4080, 4070, 4060 and 4050. At the end of the day, there will be more new and more accessible GPUs for everyone. Nvidia is totally expecting to compete against their own RTX 3000 series in the used market, but there aren't that many 'mining' GPUs dropping that the influencers want everyone to believe so that dead GPU segment is holding on for whatever comes next.
For most here, people better hope that AMD is disruptive with their pricing because Intel isn't disruptive with Arc.
Just to add, for those upgrading or new PC buyers, you all better hope that Ergo doesn't kick off because then GPU prices, from any maker, will be just as bullish as crypto.