No doubt 65 million monthly active users is good but, most of those users are probably playing free to play games, especially when you look at steam hardware survey, so many people are still on 1920x1080 followed by 1366x768......
And chances are, steam is the largest platform on PC so I doubt uplay or origin would beat those figures, at best, they would match it.
Also, PSN is at 70+ million active users, microsoft is behind with 52 million.
Quite interesting looking at the most played games on steam:
Although it is a bit pointless comparing how many users are on each platform as shown, when it comes to triple a, consoles will sell a lot more than the PC side.
How much is a 1080ti again? No point comparing something that costs at least £200+ more....
It isn't just AC:O though, it is 90% of the games out there for PC now, graphics are barely any better than PS 4 (pro)/xb1x and more often than not, the pc game is plagued with issues on release day.
I know people rant and rave about indie titles and so on, personally they do nothing for me, triple A games are also losing their appeal for me too (largely because of the state they are released on PC).
This is what makes the PS 4 even more enticing as you get great triple a games like the last of us, HZD and so on.