It's an interesting question and I don't know if there is a definite answer.
Personally, I do clean my barrels which varies from mostly a basic clean and patching the bore with oil after every use to occasional deeper, more thorough cleaning and copper defouling once or twice a year. Overall I am only shooting about one thousand rounds per year over about six rifles. I am satisfied this system is about right for me and helps retain accuracy ( at least in my mind ).
What confounds me though is, for example, a mate with on old, barely maintained .270W ( can't remember the make ) that's never bore cleaned but has unreal and unfailing accuracy ( he is a good shot anyway ) that makes me wonder, generally, how useful bore cleaning really is. My mate probably shoots less than 50 rounds annually.
But on another level of shooting I was told some years ago by a hunting guide who, in a team of guys, culled goats for DOC for several years, mainly using .223 cal ( I think, IIRC ). It was his view observation / view that rifles shot well up to around 4 - 5 thousand rounds anyway but if cleaned ( frequency ? ) were good for another 2 - 3 thousand rounds before becoming shot out.