Slightly Mad Studios today announced on social media that Steam will de-list Project Cars 1 on October 3, 2022 and Project Cars 2 on September 21, 2022 due to licensing.
What this means, in real terms, is that those titles no longer bring in enough revenue for the developer to renew the licenses. However, if you purchase the titles now then you should still get access to the full-featured titles and content long past that deadline. This is the same reason why you can still buy Steam keys for de-listed F1 titles from Codemasters and use them to activate the product you can no longer buy via Steam itself.
If you’re interested in buying a PCARS2 Steam key from a legal source and want to help RSC at the same time, check out Humble. (This is an affiliate key that gives RSC a percentage of the sale).