Your experience may be different than many. I have brewed extract on the stove. Partial mash on the stove. 3 vessel propane all grain, BIAB. I have had equal results with all of them as far as being able to brew a great beer. My 3 vessel all grain did have the most consistency though. I now have an electric recirculating BIAB system (Unibrau) I haven't finished any yet so I don't know how it is going to compare.
I have made some very enjoyable homebrews from extract-and-grains. I liked them, my friends liked them, and I have not ruled out doing that method again in the future for one-offs. THat said, I would not consider any extract beer I ever made (or have ever had from other brewers) to be commercial quality. By commercial quality, I mean from big breweries, because the vast majority of new nanobreweries popping up in neighborhoods all over the country are turning out mediocre product (yes, you can dry hop the crap out of my morning piss and call it an NEIPA and most people would still buy it).
But that aside, going to all-grain, using fresh, high-quality ingredients, I noticed a dramatic qualitative improvement over extract-and-grains.
I further noticed (a less dramatic, but still noticeable) improvement when I started paying attention to water chemistry and pH.
I noticed further improvement when I started reducing oxidative damage to my beer.
But all that came at the cost of a dramatic increase in complexity and time required to produce.
That said, someone who is not attuned to flavor nuances or who is just looking for something they can drink in quantities with their friends and catch a buzz and proudly say "yup, I made that", may not appreciate or even care about the improvements or may feel that a small improvement isn't worth the large additional investment of effort (we all have to decide where we stop on the scale of diminishing returns).
For me it is. YMMV.
***BUT...making decent to even pretty good beer doesn't have to be all that complicated. It's only as complex as you make it.