I'd considered this, but after retiring my phone number for two weeks, it became very apparent that there's lots of friends, family and services that are not savvy enough to make that transition yet. Also there's a bunch of services that use your phone number for 2FA reasons, and no, some of them don't offer different solutions. It's still very difficult to have a conversation with a new friend and demand they install a new app on their phone to be able to contact you. With my proposal above, I figure you can accommodate the normie without even having the conversation and essentially costing you $2 per year (just to keep your number active).