Music is more than just color and rhythm
Don't sell yourself short. Nothing too special about John Williams except that you think there is. When you realize that we've all got potential and stop putting people on pedestal, you realize that you are capable of good ideas as well. I'm sure his noodling isn't bad. But I think it's a bit hyperbolic to say "I'd bet his 2 minutes of random music is way better than anything we composer when trying hard"John Williams writes 2 minutes of music a day. I'd bet his 2 minutes of a random music exercise are way better than anything we compose when trying hard. And I don't know how many people compose every day like that. And is even 2 minutes of music "a composition"? Etc, etc.
tldr: A very good composer can produce maybe one quasi-excellent proper composition a week, maybe. That's 52 a year, maybe, that's 19 years to get to that goal. Not bad.
Either that's a typo, or terms "elite level", "excellent" and "thousand" mean something very different than some of us are used to.
Actually I find that some of the best music I've written has been spontaneous, not the stuff I wrote when "trying hard."
This is very subjective. And interestingly, some of my tracks of "lesser" quality get more sales because of the mood and character. So often times we are stifled because of what we think others want (by trying really hard).
It isn't so black and white in music.
I just think having that attitude of "my stuff will always be second-rate, quasi-excellent and not actually good" is setting yourself up for failure already. Part of being good is competence for sure, but there is also a level of confidence that one must have to begin with. This can help you find your unique voice, which may even result in composing something (good) John Williams wouldn't even do (because he's not you).