I for one stopped making addons because in my opinion, I'm wasting my time since the playerbase is dead. If it went F2P, I'd start again. Same can be said for many addon makers. Going F2P will 100% increase the playerbase because theres lots of people (I used to be one) who doesn't have a credit card and relies on forgetin christmas for Steam cards or something, leaving me to only play free games or the paid ones every once in a while.
People stopped hosting great servers because nobody was on to play said server. The most fun I've had while gaming was my Build & Kill server which averaged 20 players. I stopped hosting it because Blockland loving died. If BL were to be revived right at this second, it would still beat the test of time.
In game microtransactions? Sure. Who cares. You can get a cool helmet or chest decal or little charm like we already have in the game. Don't want to spend money? Don't. It doesn't affect you.