>>mikece+(OP)
Signal had 40 million active users in 2021 [1]. 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.
>>abdull+tk
I've been using WhatsApp when the nominal $1/year fee was still around, but somehow never ended up being actually charged, and I don't know anyone that did.
It's possible that they were only enforcing it in some regions, though.