I see what you're saying, but think of it a little differently.
At 3.5, you're learning to hit "pretty" strokes, which are extremely difficult to achieve, especially if you started playing tennis late in life. Maybe you get "decent" looking strokes after a while, but unless you have unlimited time to spend on tennis (what adult does?), the effort required to get past "decent" strokes will make it difficult to get any sort of regular match play in as well... There is also the tendency to become manic about having "perfect" strokes, which leads to less and less match play...
So anyway, at some point, maybe the 3.5 decides "screw it, my strokes ae good enough, I've gotta play" and then they get into matches, they see that they get about 5 opportunities to hit that sweet ball-machine fed forehand stroke per match and the rest of the time they're scrambling and getting wrongfooted and dinking back random, unpredictable balls from their opponent because chances are that their opponent also doesn't have gorgeous baseline basher strokes either. Their opponent is putting the ball back in play, because they know that in tennis, you don't win points, games, and sets unless you put the ball in play. At 3.5 and 4.0 and 4.5 as well, the game really is about who makes the first mistake, rather than who can force the winner. I once heard Paul Annacone say "One more ball is a valid strategy until you get inside the top 200 of the ATP."
So as the 3.5 gets more seasoned with match play, they learn what works to beat the opponents they're playing - keeping the ball in play, waiting for a mistake to attack, or just waiting for the opponent to make a mistake and hit it out or into the net... they win more matches, with slice, with drop shots, with poking the ball past the approaching opponent, with pushing... why? Because it works, because at this level of play, nobody is consistent enough with those pretty strokes to be able to use them in live match play with the repeatable accuracy needed to keep the ball in play. They can hit 200 forehands with sublime topspin off of a ball machine, but when they have to run all over, get set up perfectly with their footwork, and execute the dozens of tiny details that let's them hit those great shots, they can't do it... and if they could, they wouldn't be playing 3.5...
So the 3.5 is now winning a ton of matches and gets bumped to 4.0 - with the game play they've evolved - maybe you call it a pusher game - maybe you call it a junker game - but whatever it is, they're winning with that, and the one thing you don't do is change a winning strategy.
Eventually, if they are to progress, they're going to need to hit the ball harder, and more accurately, and as needs must, their strokes will have to improve to get beyond this 3.5 to 4.0 level of play. Heck, to even win at 4.0 consistently, they're probably going to have to evolve - and that pusher bunt shot will be run down by the opponent and attacked or sent back at least in a very uncomfortable way for them unless they start hitting it harder into smaller targets - and to hit it harder, with accuracy, their strokes are going to have to improve. It should be noted that by "stroke" I mean the whole thing - footwork, detailed minutiae of arm/shoulder/wrist position, swing path, use of the kinetic chain, everything - not just the loop of their racket head.
The reason the pros hit beautiful strokes is because they have to, because the people they're playing are essentially superhuman, they are logarithms better than a 4.0 or 4.5 player, and that's just the way it is.
All of this is not to say that "pretty" strokes are a waste of time. It's just that they are quite a difficult thing to develop and they take years to develop. Without them, you will not progress beyond a certain point in tennis, but if you want to win at 4.0, you can get by without them for a while... if you want to win at 4.5, you're strokes are going to have to be prettier/better still, and so on...
3.5s may have prettier strokes on a ball machine than 4.0s play in matches, but when those 3.5s are hitting those pretty strokes out and/or into the net in the matches against those 4.0s who are just trying to make their opponent uncomfortable, guess who wins? The reason the 4.0 is a 4.0 is not because they have junker strokes - but because they know how to win at 4.0, period, and most of the time that doesn't require "pretty" strokes - if you have them AND can use them in a match, more power to you - you'll not be hanging around at 4.0 for a long time though... because you'll be getting bumped to 4.5...
I've been on the recipient end of it many times....
