Success? You do know that iPad vastly outsells the Surface Pro? So does the MacBook. Did you know that the Surface business only became profitable in 2015 and was, in fact, loosing money before that?
Surface Pro is a nice product, but no one is 'playing on its success', especially not Apple. The Surface line is a strategical product for Microsoft, raising the bar for Windows 10 devices, a showcase of Windows possibilities, etc. Microsoft earns its money from software and services. In fact, Microsoft earns more money from Apple users than from Surface Pro sales.
I like the Surface Pro, I really do. And I like Microsoft. But I am not really sure where this idea that the Surface is some kind of Apple-killer product comes from on these forums. It's nice and all, but Apple is not playing on anyone's success. They look at the market and see if there's demand for a certain product, then they offer their version which usually ends up outselling everything else. They certainly didn't make the iPad Pro because of the Surface, they deduced that people wanted keyboards with their tablets (there were keyboard cases for iPads for quite a while) and decided to do their own take on that. Again, that doesn't mean they did a better job or that Surface is not a good product, just let's not get ahead of ourselves and think they actually did something because of the Surface. In fact, they started designing the iPad Pro at least 2 years ago, and at that time, the Surface was actually a financial failure.