I kind of wish everyone posting would say if they're talking about the Surface or the Surface Pro. It muddies the conversation significantly.
Between the Surface and the iPad, I can see why people would choose the iPad for things other than the name.
The Pro is better than an iPad. Period. It's not just faster, it makes the iPad look awful. It consumes content just as well, if not better than an iPad. It also has the added bonus of being what everyone thought the iPad was going to be.
Windows was not awful. Disagreeing with an aesthetic choice doesn't inherently make the entire OS awful. iOS is awful, in my opinion. You can't do jack with it. It's ugly, it's just as fast/slow as anything else out there (from personal experience). See how easy that was? Completely subjective.
The iPad is also not the original. Tablets existed years before the iPad. The iPad was the first to see wide commercial success. When I see tablets here on campus, I see just about as many Surface Pros as I do iPads.
The Surface (non-Pro) is pretty much irrelevant going forward. Full (and cheaper) Windows 10 tablets from other manufacturers and Microsoft moving toward a unified Windows platform mean there is no room for the regular Surface anymore... and good riddance. Muddying the conversation is exactly what RT did; I can't tell you how many times I had to explain someone exactly what Windows RT was (I had a Surface RT a few months after it launched), or why it didn't run the normal desktop (x86) apps like a "real" Windows device.
You are trying to explain why the Surface (Pro) is better - and as a power user, you won't get any arguments from me - but the question was why the iPad is still more popular. The Surface Pro might be as common as the iPad on your campus, but that's not the situation overall in the broader consumer market.
I think inexpensive Windows 10 tablets are really going to compete against the iPad in terms of sheer numbers over time (just like how Android beats iOS in the smartphone space), but not necessarily the Surface Pro. The "Pro" in the name really does indicate the fact that it's more a prosumer oriented device than an iPad killer like the Surface RT was meant by Microsoft to be, and the price and feature set (including the excellent pen, for instance) really pit it against ultrabooks like the MacBook Air. The MacBook Air doesn't sell anywhere near as well as the iPad or iPhone, either, and it doesn't need to. The Surface Pro definitely is more of a niche product than the iPad, but students, business professionals, artists, etc are large enough a market to justify its existence. It's a pickup truck or SUV, not a Prius or a coupe.

There's a case to be made for or against it being the best option, but it really comes down to your needs.
I would love to see a Surface Mini (supposedly the line was killed off right before launch), but Dell's Venue 8 Pro and the ASUS VivoTab Note 8 are fairly good for the price, if not as high quality as maybe a Surface Mini could potentially be. I still kinda wish Microsoft would make and release a next-gen Courier.

Their labs are capable of some really amazing stuff, like the HoloLens.