Don't buy it then?
I have no problem with the pricing; it's cheap compared to the amount I've spent on microtransactions in some "free-to-play" games, and I'm sure I'll get a lot more value out of it.
But it's nothing to do with the fact of it being "cheap" or not, they are charging existing players, the players that actually funded the development of the game much more than new players.
They are now saying that not even a year down the line, a game a lot of people paid £50 for, is now only worth £10.