As per a notification shared on Twitter, Intel is already discontinuing its 10th Gen Comet Lake-S desktop lineup, with the product discontinuance program reportedly already in action (from the 16th of December).
Update: It seems that this is with regards to the discontinuation of the Avengers Special Edition lineup, not the vanilla chips.

This means that retailers and distributors won’t be able to order newer shipments of the 10th Gen processors after the specified date. All orders of these chips after the 16th of December will be non-cancelable and non-returnable. This doesn’t mean that consumers who bought a 10th Gen part won’t get service, however. If not a replacement, you should be able to get a refund at the very least.

The 10th Gen lineup has been out for less than a year and this discontinuation notice comes as a bit of a surprise. We already knew that Intel was prepping to launch its 11th Gen Rocket Lake-S lineup in Jan|Feb 2021 and the Alder Lake-S lineup by the end of next year, so both the 10th and 11th Gen products were going to be short-lived products, but I feel like Intel is cutting a bit too close here.
The 9th Gen products are also expected to disappear from retail by the end of 2021, nearly a year after their successors. Then again, the differences between the two are too few to really tell them apart.