Scaling well with horsepower is only half the equation though. It needs to start with a good foundation too. Syndicate plays really well on a PS4 at 1080p (edit: 900p), so the lack of comparative performance on the PC is inexcusable. Ubisoft's policy towards PC is that they don't have to spend money on optimizing for it since people can always throw better hardware at it. This isn't a policy we should applaud.
I believe the PS4 version of AC:Syndicate is 1080p30 with medium-high settings, so you have to take that into account when comparing to how well it plays on the PC. Most benchmarks are done with 1080-1440p at Very High/Max settings.
What you say is true for a lot of Ubisofts work though. Watch_Dogs was a disaster on the PC if you wanted to play on high texture settings, even with a Titan level card with VRAM overkill. The Division is also questionable with how it performs on the PC on high end hardware. I've put the game off for the time being since it framedrops below 60 often even on non-max settings on a 5820k@4.4|980Ti@1.4Ghz.