100% agree. For myself my situation is a mix of both, so I decided to upgrade for my own piece of mind mainly.That really is my point, we, the photographer , ‘feel better’ but the viewer really doesn’t see the difference. Now it depends why we have this gear, who we are shooting for etc etc. if we are shooting for ourselves and we have the disposable income then the new stuff is a no brainer. If we are shooting for others on a budget the equation is very different.
I will say though, the technical qualities of the final output are just one part of the equation to consider when you’re shooting with a team of people (on a fashion shoot for instance). The improved autofocus means I don’t have to ‘overshoot’ to ensure I have a good frame with perfect focus. I can move on to the second and third look with more confidence - saving time and being in a more positive mindset / less stressed. I suppose that helps everyone feel a bit better on the shoot in those situations. But once again it’s a ‘nice feeling’