If you get more and more users do you say sorry, we are an exclusive club of 2m[1] we won't let you have a chat/group/event with your other friends who were late to the party.
That sounds wrong.
[1] rando number, large enough to brag about probably small enough to have easier support problem
Scale is multi-dimensional. It's not just a question of user base; there's also all the different features they have added over time as well that they have chosen to dedicate resources to. Also, support has cost, and putting service as a key feature of your brand often means sacrificing margins.
