The horse this author decided to whip in support of his cause célèbre is 3D Touch. Perhaps you could argue mobile usability is getting worse but 3D Touch is hardly a good example to pick.
Comparing 3D Touch to adding a 'right-mouse button' is at best a faulty comparison. 3D Touch does not replace already-learned interactions; it does not require the user to learn something new. It simply adds new ways of interacting for people that know its there or those that discover it by accident.
How can that be making usability worse?
The beauty of mobile devices is there are so many ways to interact with a touchscreen in an intuitive way, the complexities are easier to hide. Apple have added yet another way, but it is entirely optional.
Perhaps the author would care to explain how if usability on mobile is so bad, how does my 2 1/2 year-old intuitively and effortlessly navigate children's programs on an iPad without any instruction at all? She'd need to be at least double her age in order to do the same thing with a mouse and keyboard.