Signal had 40 million active users in 2021. With 14 million in infra cost, that comes to .35 per user/year. Total expenses are about 33 million, so about .825 per user/year. All in all that seems very reasonable.
https://news.ycombinator.com/item?id=38291950
So it should be pretty easy to cover your own costs and maybe that of a couple of friends to make the transaction fees worth it :)
They were kinda forced to, having to choose between two evils: https://community.signalusers.org/t/signal-blog-removing-sms-support-from-signal-android-very-soon/47954/57
Haha exactly, by that calculation $1 a year would cover you and two others. Get that family onboard :)