I've gotten instruction from very prodigious practitioners and their opinion on the rules they are following is what I stated. You can get through introductory jazz or classical piano and also basic orchestral composition and the patterns or rules you'll know are about are going to be super basic and even very sophisticated niche and "intellectual" music is not being created by people with more theoretic knowledge than that.
That's why I talked about implied reliance, as opposed to what people explicitly "know about". Surfacing the actual practical rules behind what practitioners are doing is arguably a theorist's job, but many theorists are not fully comfortable with the kind of thinking that this would require.
(The 'Rule of the Octave', which is the kind of rule I'm pointing to, was quite exceptional in being explicitly taught in actual published treatises about music - and even that was practically forgotten later on; it's not usually taught in "introductory music theory" classes even though it arguably should be!)
If anything, it's just the opposite. The 'rules' (again, this should be understood as patterns, or perhaps rules of thumb) practitioners implicitly rely on are far more complex than most theorists are implicitly comfortable with. This is why bookish music theory was mired for centuries in pointless discussions about acoustics and ratios, or some incredibly weird formalisms for representing meter, whilst practitioners got on simply focusing on what sounded good.