For me it went worse around 12k max users at Sunday evening. I found that a manageable number. There were sufficient players online to give you that warm fuzzy feeling but not too many to feel crowded.
60% of the game is for me athmosphere, you don't get the feeling of vastness of space when you cross into lowsec and see at least 4-5 people in every system.
Besides that, Eve used to be a niche product. You had to be persistent to work yourself through those first weeks and get the damn char going. Unfortunately, that seems to have somewhat disappeared for new players.
... and most important, as a group or userbase grows, the number of asshats grows exponentially. Most people are too immature or just incapable to react in a mature or civil way. That counts in real life but as well in these kind of environments. The posters of old times are still there and many are still playing, but they refrain from posting afaik.
It's a sad thing, but the worst thing that can happen to nifty, quality or classy products is that they could go mainstream or become popular. That's just how it works. Once you get a broader base, you have to pull more compromises to keep them all happy and at the same time more people will be nagging.
The good thing is that CCP at least seems to have struck a nice balance over the years, between playerdriven changes and their own vision. Another positive feeling is that the people that usually complain or whine, usually do the same in real life, which gains them absolutely nothing
In the end I think your statement is mostly right, but consider it also depends on yourself. If you feel you're becoming victim to the negative athmosphere, look for a change. The fantastic thing in the game is his diversity. You don't like this or that, go do something else. You don't like certain people ? Look for another corp, etc...