When? I don't remember them ever being less stingy with diamond rewards, and I've been playing almost since the beginning. I also have no trouble staying competitive, buying just the daily diamonds (and sometimes not even that). Yeah, I won't get 1st place in any contests, but I don't care about that.
Also, unfortunately, games that run as services cost a lot more than $50-60 a year these days. WoW costs $180 a year, and the supposed free-to-play MMOs can cost much more than that.
I think your particular issue is that, for you personally, you don't feel "competitive" unless you pay $50-60 per (month? week? contest?). There are players who have to spend thousands a month to feel "competitive," and I'm fine paying $3 or less.
Now taking a step back, it's possible that a different pricing scheme would make them just as much money. What if diamonds cost half as much? Would people spend less money or more? It's hard to tell. But regardless, you'll always be competing with people who spent more than you.