Why do people that do not donate play such servers?
Call me crazy, but playing non-donates on a donation-filled server is a hell of a challenge.
I played EShadowRO(re-learning RO all over again) over three years ago, after I stopped playing RO for nearly a year(before then, I had been on SlashRO, Ethereal, Ceres, Titan, etc). When I hit Max, I took my LK to PvP and was apalled at what I saw...four slot donation wings, the availability of purchasing your build(You could "buy" a MAX on one Stat, as many times as you wanted until you had all 255's), God Items available through donation, MVP Cards were able to be purchased...it was scary.
Especially for somebody who never felt the need or want to donate to a server for items.
Then I saw something that got me and my friends thinking: The donators...played like sh*t. No smarts whatsoever. The things that kept them afloat were having a sh*t-tonne of STR, AGI, and PD. There were a couple here and there who knew their stuff(two pinoy players with donates would rape the entire lot of them), but that was it.
Therefore, we started exploring and exploiting new options. None of the players knew what an Incant did(SAD), and the players that did were banned before I joined, so it was general knowledge that Incant "just sucked your HP and that was it". Used them on my DD/DEX Sin X, and went Crit on my 2HS LK, and AutoCast Bow on my Sniper. Friends did the same, finding what works and rolling with it.
Didn't have Wings? Two Engagement Rings(+5 All Stats) did the trick just fine. Didn't want to donate for Megs? All of us would farm Zeny for a day or two and have enough to buy two or three from somebody selling them in the Vending Area(usually about 700-800M apiece). Who needs Sleips when Moonlight Flower and AGI Badge work just as well?
Eventually the donators found out that they were s*** and complained about it, while those who couldn't handle the fact that they couldn't win by buying their way through it...left.
tl;dr: "Donorfests" can be fun if you know what you're doing, and listening to both the whining in Ventrilo and the BAWWWW-ing on forums after you show them what-for is incredibly satisfying.