The Pi will struggle because we're used to things like hardware acceleration of desktop graphics etc., and when an OS that normally uses such features suddenly doesn't have them, that's what you get: A jerky, sometimes unresponsive interface. In fairness, try having a few windows open on your Workbench screen on top of each other and switching between them without a graphics card. Once you get above 16 colours it'll crawl. The only reason it was mostly responsive was because it *did* have hardware acceleration tightly integrated into the OS.
Nowadays every computer is far more powerful than you need so it's easy to get lazy. But people don't really want innovation, they want to do what they do a little bit faster. And what they want to do is vastly more complicated. Something as simple as browsing YouTube and Facebook is actually a huge deal, and a little bit tricky to do from scratch. If you throw in MS Office, Photoshop and most mainstream games, you've basically only got one choice: Conform to what's already there. If something's new and original, that's great but it'll be of little interest to the population unless it does those main things that people expect of it.