If memory serves, this was one of the reasons the other place which must not be named was created - to show that it was possible to set up a forum with all these features for free when MN were asking for people to pay for them. Asking this when many people were being furloughed and struggling financially due to the Covid impact, felt unfair to many posters.
Over my dead body would I pay for an internet forum of any kind!
Anyway, the ignore posters option is actually not even a premium or luxury feature imo. It's a way of staying safe on a forum where some people are downright bad and out for making trouble. I can sort of see why avatars etc might be seen as a luxury thing, but then plenty of other places do it, so 🤷♀️.