Originally Posted by NLBwell
I think the critical part of your statement is "don't have coaches." If someone is coached by a good tennis pro and is very mindful of what they are doing and are willing to work very hard, they certainly can improve significantly in a year or so.
If you don't already know what is correct, without an outside view of what is wrong and, importantly, what to do to improve it, just practicing a lot will only get you so far.
I know a couple of people who were really dedicated, who worked closely with a good pro and moved up to 5.0 in only a couple of years. Yes, it is pretty rare.
Also, a lot of pros aren't that good.
there's this kid (15, 16 yrs old, i think) that used to show up every Saturdays at the park where i play. He had a coach and the coach did a great job on fixing his forms, all of his shots looked good.
One day, his father asked my hitting partner and I if we would want to play doubles. We agreed and proceeded to triple bagel the father-son team. It turned out the kid could only handle the kinds of ball that his coach feed. If it was slower, faster, higher, lower, or beyond the ideal hitting zone, the boy couldn't handle it. The father, although he didn't have as good of a form as his son had, he could handle most of those balls.
The coach was pretty disappointed but the kid never played other players. he only practiced with his coach. Not sure what happened but he stopped showing up at the park.