The ipad DID evolve....but it was Microsoft who took it to the proper level and called it a SURFACE 4. It's a touch pad with lots of apps, it's a robust computer running most industry standard apps. You can attach external storage, external monitors, it can work with a mouse if need be, etc, etc etc.
This is what happens when you implement features which look great on a spec sheet but don't necessarily translate to a great user experience in actual, real-world usage.
The Surface Pro is a touchscreen computer running a desktop optimised for a mouse and keyboard interface. It has a ton of apps not optimised for a touchscreen interface either. The people who would hook it up to an external monitor and mouse are those who would be working at a desk anyways, aka the people who would be better off just getting a laptop.
Contrast this with an iPad that sports a very responsive touchscreen, running an OS built for touch from the ground up, running native tablet apps optimised for touch and direct input, and designed with mobility in mind (eg: long battery life, inbuilt 4G, iOS is easier to use and less bloated and buggy overall). All this make for a great mobile computing experience for people who desire to work when they are not at their desk.
And if I want to mirror my iPad to a larger display, that's what the Apple TV is for. No need for wires and cables.
I 'get' why Apple didn't go this route: it would have obsoleted the low end MBPs with their huge margins. And now they are playing catch up in a market space THEY created. If it weren't for iOS (vs android's **** OS) it would be the same on the smartphone market although the iPhone 7 is a huge disappointment....and yes, I own one.
Apple didn't go that route for the oldest and most undeniable of reasons - it sucked and made for a lousy user experience.
And if we look at the tablet market today, the iPad is still pretty much the only tablet which matters. Android tablets are dropping like flies. People aren't buying them unless they are being sold at bargain-bin prices, and as the saying goes - you get what you pay for in the form of shoddy hardware and lack of software support. Conversely, the ipad continues to benefit from a thriving app ecosystem and third-party accessory market.
The Surface is a tablet in form but not in essence. If I wanted to do more "PC-esqe" tasks, then yeah, I would use a Surface Pro over an iPad, but for tablet-esqe tasks, my money is still on the iPad each and every time.
I rarely say 'If Steve were still alive', but, I gotta tell ya, if Steve were still alive Apple would have pivoted 3 years ago to a pad resembling the Surface, a smart TV box of some sort (not the ATV...it's still a 'hobby') and then maybe into the jewelry market aka watch (which is a device STILL waiting for its first 'killer app'...after 2 years).
Somehow, I doubt it, but considering that Steve is long dead, we will just have to agree to disagree.