Dude of course you have to be a better photographer. That's a given. It's a bad argument though. The A7RIV has better AF, Better Dynamic Range (advertised, still needs tested), Dual Card Slots, Better EVF, higher FPS burst, much higher resolution, along with more native lenses. Those are quite a few areas of superiority, which for some will make it a better stills tool.
Your argument is the equivalent of saying there's no point buying a BMW over a Subaru because you need a good driver to get it around the track. That's true, but a good driver might choose a BMW for it's better onroad-track specs and be faster because of it.
A better photographer will be able to use a more capable tool more effectively or efficiently, and for some the A7RIV will be a better tool.
We all know this. Sure it's not competitive for video, but for stills it's a pretty nice piece of gear.