Well Mick3391, for an op that you said you thought about deleting after you posted it, it's elicited some pretty good comments, imo. I have to agree with the posters who said that qualified instruction really does help, and for some it's absolutely necessary.
But I also agree with what I take to be your main point(s), in that the key to improvement is work. That is, work without instruction sometimes results in improvement, but instruction without work doesn't.
Hope you're having a great holidays, and if you're ever in my area ... let's hit some tennis balls.