Also the iPad Pro refresh rate is double that of Surface; the screen is significantly better which matters when you spend 8 hours a day looking at small stuff.
iPad Pro is also thinner, lighter and has a far more powerful processor.
If you can't install your environment locally, you might as well use a $200 android tablet...
I have played with the Surface quite a bit and I know a few developers who use them (or have used them and given up). Partly it comes down to not wanting to use Windows.
When it comes to development, what's the use case besides a terminal client?
You can't develop anything native, because of iOS.
You cannot do webdev, cause only browser you can have is safari.
Cannot do embedded stuff due to lack of ports.
I think I described that I work on remote servers belonging to my customers, so mainly I use a terminal and a web browser for that. I don’t do native development (anymore), I don’t do embedded programming. I do sometimes do front-end work and I have a Chromebook (and tools like Browserstack) for that.
I don’t try to do everything myself, or have computers that can do everything. I hire a lot of work out.