Unfortunately, that is what modern gaming has (d)evolved to.
Why give players who achieve XYZ a reward when you can just sell that reward for money?
I am sure there are plenty of game designer at arenanet who rather have the players earn rewards instead of buying it. But a corporation just wants to make as much money as possible, so that is not going to happen.
Don't forget that, as time goes by, more and more gamers will never have played an online game without microtransactions.