They aren't killing the game.
One could argue that it favors the wealthy, but that won't stop the rest of us from trying harder to match his stats, surpass his stats, bounty him over and over again, and show that money can't buy everything
I've put a lot of money into the game myself but refuse to buy a character - there is no fun in that. I want some challenge in the game.
But even if you don't have real money to spend, you can strategize on how to best use your earned credits to obtain legendary items. That in itself is a great part of this game. For me, though, I'm too impatient, which is why I bought some stuff.
But I'm done paying for a while - going to take up the credit challenge and save save save!