I definitely feel like I'm getting better with every tournament I play, every mistake I make. Just like the motto, if you burn yourself once on the stove top, you won't touch it a second time.
If I had the feeling that I can't learn from my mistakes and that I'm getting worse and worse, I probably wouldn't play anymore because my focus is on reaching more and more final tables.
Another thing to keep in mind is that the average player nowadays has much better skills than 15 years ago, because nowadays you can easily improve your knowledge via internet, tutorials, streams, etc.