If they plan to shut it down for Foundry customers, there's probably a "yield issue" that is being hidden from the public. Last time there was a "yield issue" it turned out to also be a reliability issue. 18A introduces complex new features like backside power delivery which is a major structural change to the die that has never been done before. There is a very real possibility that thermal cycling continues to be a concern as it was in 10nm/7nm which lead to the neverending story of 14nm+++++. We just won't know until some enterprising YouTuber ends up publishing a detailed analysis of public reports of CPU failures in a year or two. Reliability issues can end up taking years to fully root cause and mitigate.

Personally I'd rather watch the 1980s Neverending Story movie rather than see Intel continue to push out even more half baked products into the market again on yet another broken process node. I really hope I'm wrong.