Ah yes this was discussed a little on the initial design doc, the main problem being, if you say "first come first serve" then a bad actor can easily snatch all the good names and try to sell them. So it does the opposite effect where every community is named like "ThePhotographiesLovers". There could be a mechanism where only the biggest gets to keep the name or with community voting but then that means one community can take over another which is terrible UX (one day you're on food, the next day you go on food and see a completely different community).

The way things like ENs or domain name solve this is via rent (you need to pay a small fee to keep the name) but I'm not sure people would be willing to pay and if the price is too low, squatters may also want to do that as well. and pay, say 100$ a year to keep 100 domains.

I feel like this is is a bit of a tradeoff, people can create and maintain communities more easily and without the mental block of "oh is this worth me spending money on it"