The thing about creativity is that it takes practice - just like anything else. Rare is the person who does not practice and yet is gifted with ability. All of the famous musicians mentioned in this thread practiced to get where they got. Luck and determination helped.
Practice in writing music is the same as practice in playing guitar. If you only play the same song over and over, or songs with the same 3 chords, that's not practice. Practice is an intentional effort to stretch and improve a skill set.

I help with a songs in progress workshop every month and one of the first questions we ask is "what were you trying to do?". Sometimes they don't know or get upset because we mention a structural flaw in the song. The over all concept is to help them succeed in finishing what they wanted to do - or just say "that's nice" if that was what they were looking for. One of the guys running it makes the statement "I can write a good song about a bottle of water because I know the rules of the craft". Which puts some folks off because they thought it was like a gift from God.

Sadly I think the music pushed on the public has gone the way of art.
https://www.prageru.com/videos/why-modern-art-so-bad

The numbers may be dwindling on the critique pages because either the youngsters don't feel the need to practice or the older folks think they practiced enough to get by. Losing some of the more prolific posters has obviously had an effect.