Hmmm. The Cybertruck and the Semi are new vehicles, still in design, and without manufacturing machinery and assembly lines already committed. So I can see the feasibility of incorporating new battery cells in those. But the Model S design is set and the manufacturing lines are in use. The new cells will require new battery packs, potentially different cooling systems, and most likely different chassis architecture. I cannot see the new cells being in the Model S without a major revamp of the platform, and I doubt Tesla will do that for a low volume model like the Plaid will be. I could only picture that if tesla does a major revamp of the Model S (and possibly X?) architecture, inside and out, which sounds like a major investment. They would need to do all their testing all over -- including safety testing for all their sales markets. The Model S and X volumes are so low, it is hard to imagine that investment being prudent and worthwhile. They have not even converted S and X to the cells being used in Model 3, which would be a smaller leap (but still would be disruptive to manufacturing and would possibly require testing, I think).
Tesla has too much development on their plate -- Semi, Roadster, Cybertruck, and now the Plaid.
Frankly -- and as a Model S owner, I hate to say this -- I wonder if Models S and X have served their purpose and will not be further developed. The Plaid model is a sort of extreme stretch of the current platform. Maybe it will be the swan song...The Model S and X do not really fit with the high volume, low quality/low service model that tesla is currently operating. For continuing sales at high volumes, Models S and X require a different sort of buying/service experience, which existed before Model 3 but which is largely gone. I wonder if the pricier models are just not needed for Tesla's purpose to "accelerate the world's transition to sustainable energy..."