People's 3DS games are already being found to be unplayable after sitting on the shelf and switch games will meet the same fate. Nintendo has been failing both paying customers and preservationists for a very long time now. Piracy will again be the only way people will have to play many Nintendo switch titles. In other cases, people will have to wait for nintendo to release a limited selection of overpriced (and sometimes edited/censored) versions of certain older games on whatever future platform they're currently pushing.
I did some Googling and there doesn't seem to be an epidemic of 3DS game carts failing, I can find a few isolated reports but that feels as expected to me.
