If a player is so inclined and actually wants to improve, tougher equipment could possibly break them of laziness and lackadaisical play that they are used to getting away with.
You can't actually make anybody do anything but a training device can certainly point out certain things to a player that he may not even have realized. Sloppy play on loose equipment just becomes a habit. Of course you can play precision on loose equipment, but you probably won't.
It also should be said that some tables just play unfairly. I've played on tables that just spit out perfectly hit balls. I should be allowed to expect a certain result when I hit a ball.
I 100% agree tighter pockets makes you pay more attention, if I'm on a loose table I'll definitely shoot shots I wouldn't on a Diamond. I would be McF***ed if I played on a diamond today because I have only played on loose tables for the last 10-12 months.
But...put 10 people who have never played pool in a room and tell them the best player lives. One of them will have the skillset to be the best, the other 9 - well, you get the idea...
Think of Olympians, you don't think they've put those 10,000 hours in and they still come in second place? Some people have it and some don't - no amount of training or equipment will change that.
There will always be someone better and no matter what happens - those tight pockets will not improve the play of people who just don't have it in them.