This sort of issue crops up in any gear-centric profession or hobby.
Basically, ever since it was possible to gain entry to an activity simply with money, by buying a piece (or pieces) of equipment, you have many people who feel that somehow getting better equipment will improve their performance. Sometimes this is true, and in the case of cameras, it's partly because of all the astonishing things they can do these days, allowing somebody with no clue what they are doing to put out an acceptable image.
But the fact is that for the most part, it really doesn't matter what the piece of equipment is, it matters who is holding it. That's not ego, it's just the truth. I'm also a musician, and I experience this every day - the music instrument market is not driven be professionals - far from it. Most pros don't even materially participate in that market - they either have the instruments they are happy with and retain them most of their lives, or they are given them through endorsements. All the instrument manufacturers stay in business because of the people such as the complaint is here; people that desperately hope that trading a few thousand dollars will net them a better end result and performance. They're not willing to put in the THOUSANDS of hours that it takes to truly master a craft or art.
The problem with photography is that cameras, lenses, etc cost money. This gives the buyer some false sense that by paying, they are getting something and are owed something - a response we're all conditioned to. Consider writing, as a professional. The cost of entry is exactly zero - one can begin writing a novel, or newspaper columns, or articles, or whatever, for the cost of a pencil and piece of paper, which are freely given out in our society, and then by adding their time and talent. You don't see any of these discussions in pro-writing forums - because at the end of the day, there's nothing to blame but yourself if the end result is not what you want. The same is true of photography/videography, but it's hidden behind this mask of the cost of the gear.