I absolutely love lockboxes in PWE games...
They drop all the time and they're worth a few coppers every time. It's a steady source of income.
If I remember correctly, our own City had it's share of people shouting that it was 'Pay to Win.' Over the seven years I had in game, I could never see it. My game was never effected by whether or not somebody else decided to pay real money.
PWG games (which I do play regularly) are not all that different. It is entirely possible to ignore lockboxes and still have a satisfying game play experience using only the items that can be found in game.
In fact, I consider it a challenge.
Anyone, no matter how horrible a player they are, can beat a game by spending money. This is a lesson I learned playing M:TG may years ago. But, like in that game, I thought it was more fun to use whatever fell into my hands and figure out a way to win.