No, you absolutely cannot "create a superstar" gymnast, or a "superstar" chess player or poet or computer programmer or anything else. Superstars are by definition rare and unique. If all it took to "create" them was early opportunity, good training, and hard work, there would be no such things as superstars because lots of people work hard and can access early opportunity and good training.
Also kids can love gymnastics and have a great attitude and work very hard at it for years and just not be all that great, physically, compared to others. And some can be really good physically compared to others, but just not that into it mentally! In either case, progress eventually slows or stops. Progress is at least as much mental as physical.
This is why I cringe when people talk about "building champions", "creating Olympians" etc. We are talking about human beings, not Frankenstein's monster. We can expect there to be thousands of variations and consequently, thousands of variable possible outcomes even with exactly the same training and opportunity.
For example, it seems obvious to me that a young child (let's say 3-4 years old) doing 3 rec classes per week would progress more quickly than a child doing 1 class per week. Just from a strength and endurance perspective, it seems like it would make a difference right? Or do you think it doesn't matter?
I know this would seem to be the case, but in my experience this is not always or even mostly true. Some kids can get more done in less time, and some coaches can as well. Kids who are not in gymnastics (or any sport) can develop strength and endurance just being allowed to do kid things, like playing running around games, riding bikes, jumping rope and climbing trees. (In todays world we often do not allow kids to do these things to the extent needed but that is another conversation entirely.) And "progressing more quickly" is not in any way an assurance that a child will someday be a superstar or even all that good. In fact I have seen that (early success, early intensive training) very dramatically backfire with some kids I know. And in any case, eventually whatever limitations a person has (and everyone has some and some have many) will slow their progress, while others who progressed more slowly at first will catch up and surpass.
My daughter's pretty new to gymnastics, but also participates in other activities. Some activities (karate for example) recommend at least 2 times per week (some young kids come up to 4) to help develop skills, muscle memory and familiarity with the program. The cost of karate is the same whether you go 1 or 4 days per week, so it's not like they're just making that recommendation to make more money.
I do not understand that (4 X costs the same as 1X) business model. Is that typical of all karate? I
can see why they would want kids who go at least 2 times a week, because that would lead to the teacher not having to go over the same things as much and that helps the whole class be more organized and progress more steadily and uniformly. This is why when kids start on a gym team or even preteam, they usually start coming at least 2 to 3 times a week. I think the philosophy of rec gymnastics is a little different.
Rec gym classes are typically once a week (I imagine) because most kids are not wanting more or their parents cannot afford more. But as far as I know, it is perfectly ok to put kids in more than one rec class at a time if wanted. (Although yes it will cost more at most and possibly all gyms.) Since my kids all really enjoyed gymnastics, much more than other sports, we have had all of them in rec class 2 times a week for at least some of the time they were in rec. (The older two eventually went to team) I have no idea if that 2 times a week in rec made any measurable difference in their overall progress though. Certainly in the long run for my older kids, it has made no difference.