50$ for each person who wants to play the game in early access is a lot of money. Just in the forum poll there were around 900 people who said they would buy the game for 50$, and that is 45 000$. And since a lot more people are going to pay for it than just the 800 who answered a forum poll, you can expect for than 100k profit from this. If every MMO player on average gave 50$ to the game during its lifetime, MMOs would be a lot more lucrative than they already are.
Also no, “we” aren’t just paying the 50$ to get to play the game earlier, you are. I would have given them at least 20$ in donations if they had a donation button and I wasn’t interested in anything the cash shop offered and the game was free from the start. Basically, some of us actually wanted to financially reward IMC games for making this game.