Perhaps strict legislation against crypto fraud and zero-confirmation transactions for sums below $50 in physical shops will become popular because it's the simplest solution.
The only thing I have against zero-conf transactions is if you submit a tx with a sufficiently low fee, it may get kicked out of the mempool before it's added to a block.
I'm not sure that the risk is really comparable to starbucks accepting tap without signature or pin for low cost tx's via credit card, since there's only going to be so many people buying coffee with a stolen card. OTOH, everyone who bought coffee could pay 1 sat per byte, and then during high network congestion, all those low tx fees would be dropped from the mempool. It could result in days of every crypto tx being lost.