I consider myself an excellent player. Where do I consistently score higher? On machines I know the rules inside out and on which I developed successful risk reward strategies. On other machines I have no specific strategies, I play great shots and amazing saves but, surprise surprise, I am not consistent.
So in my opinion, once you developed solid technical skills, it's all about knowing the games rules, having proper smart strategies, and of course being able to stay concentrated over time (a mental skill, but also linked to phisical stamina). In a tournament you also need to be able to give your best under pressure.
Also fundamental is knowing a specific machine well, or learn it quickly. Maybe top players spend more time reaching a location in advance?