> Or if there are patents that would block a startup. Given patents usually expire after twenty years it seems very unlikely there would be anything still vali

> Or if there are patents that would block a startup. Given patents usually expire after twenty years it seems very unlikely there would be anything still valid for CRT manufacturing (at least for these arcade machines from the 80s. There may still be a few flat CRT / WEGA patents and the like that are still valid from the mid 90s, but they won't be valid for much longer either).