As an amateur musician trying to push my abilities, I have to agree, but I think there's another factor at work: How often do we see the glamorous side of musical performance and how often do we see the tedious play it over and over and over until it's perfect practice sessions? If anything, even at the higher levels, the repetitive practice doesn't go away, it has to increase to see ever decreasing return on time invested.
That's very true, but at least for me, being an amateur makes the repetitive practice sessions much less boring, and even more importantly, much less stressful, than they would be if I was (still trying to be) a professional. If I hear a song/piece/solo/part that I want to play, I practice it till I get it right because I love it and being able to play it correctly would make me happy. As a professional, you wouldn't (always) have that, you would feel pressured to get it right so you can collect your paycheck at the end of the day.
I guess it all comes down to mindset, but I don't tend to _excessively_ push myself when I'm just playing for myself. Yes, that probably means I'm not reaching my full potential, ability-wise, but it also means that I can continue to enjoy playing and making music.
