Most wallets are already a paid service. They receive their money by way of transaction fees that are inciuded in addition to standard network fees. Most are in 0.5-2% range, so it's pretty reasonable.
Yea definitely especially some of these lightning wallets
For the most part, their fees are very reasonable and you don't even notice them. And for the features they provide, I'm happy to give them a small bite at the apple on all my receives. When it comes to money handling, I think it's better to contribute to a reasonable salary for the devs than to rely on the goodwill and sustained interest of someone who's doing it as a hobby.