Simple they want money
you liked the game, buy premium
you then notice bugs you report , but you already paid so they dont care anymore since they got money already :D
you leave
some other pleb joins , likes the game, buys premium, notices the bugs, but since he already paid support doesnt care anymore
he leaves
cycle continues :)
also not to mention
there are a lot of bots ingame , logged in, seen like a lot of people just autocombat in new area :D