The cheeky thing with FDev is they've already monetised half of that with avatar cosmetics, pre Legs
But don't fear, interior cosmetics have always been on the cards
(And personally I'm cool with it. It's optional, doesn't mess up gameplay design aspects, and means Legs are more likely to actually happen)
The ways to monetize ED are endless [yesnod] However there is a magical line FDEV can't cross, and that is mostly related to time. If too much time
pass, people will lose interest and move on, some will return but you want to keep the people interested as that would generate a steady income.