You are correct that some modelers will build at a certain level while many younger modelers will surpass them early on. You should build for yourself and your own enjoyment and no one else.
There is nothing wrong with building a kit to whatever standard you are comfortable with and posting photos of it on the forum. If you do this though, then you are bound to get either the faint praise "great jobs" as well as the minor critiques. You can chose to ignore them or make a note of them.
It is difficult for viewers to know if you just want to post the kit for all to lavish faint praise upon or if you are looking for serious constructive criticism unless you state your desires along with the pictures. I've seen plenty of modelers in the armor forums post pictures and several days later post something along the lines of "156 views and no comments?"
I don't think anyone who does give pointers insinuates that doing it their way will make you as good as them. Some people are limited by budget, availability of materials, or have physical limitations (eyesight, all thumbs, etc.) or mental limitations (patience). Most people post pointers to help you do something better. Again, you may chose to ignore the comment, but I rarely see any harshness or malice in a critique. Critiques are just one method of increasing your knowledge base. As you point out, reading "how-to" responses are just as valid as are reading modeling books.
I personally find modeling books and magazine articles where the author takes you step-by-step through the construction phase using photographs and text to be the most valuable to me. But that's just my personal preference.
I also believe some people are pre-disposed to be better modelers than others, just like any art form. I also believe that the modeler who builds model after model will eventually increase his or her skill level just by repetition alone. Will the so-so modeler who builds hundreds of models be as good as the pre-disposed highly skilled modeler who is on his 10th kit? I don't know, maybe maybe not. It's hard to tell because it depends entirely on the individual modelers.
But getting back to the original point of this thread, I rarely see any face slapping critiques and the FSM Courtesy Police have fostered an environment of gratuitous back slapping praise on this site, regardless of the skill of the modeler. This is the one site on the web where a novice modeler has little to fear regarding harsh criticism of his or her kit.