There is hope to get better.
Many years ago I used to play Open-level tournaments. I then didn't play for a number of years and came back as a 5.0 level player. Age and injuries to my shoulder, elbow, ankle, and knee, some keeping me out of the game for lengthy periods of time, dropped me down to 4.0. I've been fighting a tear in my achilles tendon for the last couple of years which is slowly getting better and then last winter tore some cartilage in my shoulder. I played very little this summer, however I did practice what I was physically able to do.
I worked very hard on the backboard and drop-feeding myself trying to fix my strokes, re-learning them almost from scratch, and driving out the habit of lifting my head to look at the opponent which almost destroyed my game when I was teaching (lifting up to see what the students were doing during drills). As my shoulder and achilles gradually got better, I started hitting more seriously, and learning to serve with what range of motion I did have in my shoulder. With rest, time, and dissolving cartilage chips, everything gradually got better and I was able to hit with friends of mine fairly consistently. Still, I went out to the backboard or fed myself balls out of the basket working carefully on form almost every day - getting rid of the sloppy habits accumulated from injuries and lack of movement, working on every type of shot.
Finally, my shoulder felt much better and I started to learn to serve much more normally. I now go out and practice serves quite often, re-learning all my serves again. Not all the way there yet, but getting much closer.
I'm now often dominating in the higher level 4.5 doubles I play. I'm beating my friend I who I historically was even with. When coming back from injury he was beating me 6-0,6-2 or so pretty much every time. Thanks to him for putting up with me. Just beat a guy who I wouldn't even have thought of playing a few months ago because I would have had no chance, winning 6 of the last 7 games, just overpowering him.
There are two points to this:
1) Even though for long periods of time where it seemed improvement was not coming at all and I had thoughts that it was all in vain and I would now be a 3.5 player, all the work finally did pay off in getting my game together.
2) If someone is wanting to improve to a higher level, are they putting in the many hours on the practice court it truly takes to do it?