Lol it's funny how you are just ignoring the facts and making up senseless points.
1. If you count in the UnrealEngine 2.0, which is basically the same, a lot.
We won't count UE 2.0, it's a different engine (version) and I at least am talking about RO:O.
I did a quick search for UE2.5 powered (MP) games:
SWAT4 - there are still many people playing it, I'd say at least as many as RO or maybe a few less. But you can always find a server(I'm still playing some coop myself here and then). Plus it has SP and various MP gameplay modes.
Raven Shield - There are still enough people playing it(mostly vegas haters), maybe a bit less than RO(but that's just my guess last time I played was half a year ago, could be even more players). However this game other than RO atm has 3 successors.
Dark Age of Camelot - Uhh, 45.000 Players
Americas Army - no comment needed here I guess
2. No one. Have you tried finding a DoD server to play on recently?
Uhh, you got to be kidding here. I just did a quick search and found at least 70+ servers(no password, has users playing). I even controlled 10 20+ servers if they were just filled with bots, but nope there were real players.
And I said 'comperatively big success for a realism focused game' so forget about CoD or UO.
You don't have any numbers so don't talk as if you'd know about that.
I also posted a few ways in which RO was 'successfully revolutionary' to suit your definition of the word, but if you insist on ignoring them, do as you please.
For the XXth time: Those were nothing but a few innovative features that may have made RO special however did not revolutionize the genre or anything.