Is the clear used on Sonic games from the 70s no longer a possibility? Or was such treatment not used since then due to cost and the desire on the part of manufacturers for games to eventually wear out to create demand for new product? (See the latest Special When Lit where they dig up an old recording of Python Angelo saying he wanted to use polycarbonate but wasn't allowed to).
With the changes in the market toward home collectors and preservation, it would seem ensuring the highest quality and preventing damage (which results in bad PR and expensive fixes) would outweigh the old replacement/cost concerns.