the kids i see at the skatepark have like a big notch that goes the length of the rollerblades and there is one wheel in front and one in back, and i see them 270ing onto big handrails like its nothing, sometimes even 450's shit like that would never be possible from flat on skis. skiing and rollerblading are very very different, if you want to compare a sport similar to skiing compare it to snowboarding.
i played roller hockey for like 5 years and even did some freestyle stuff for awhile before i started skateboarding, and skiing and blading are totally different, with skis you have boards on snow, with rollerblading you have shoes with wheels, the only similarity is that we both face forward.