The BBC has accountants and business suits too of course. Far more of them now than ever, but they aren't running the whole show. The creative types still have a greater say in whether shows are continued or discontinued. It's odd really. Typically in a capitalist model market pressure should push the quality of shows up, and on a technical level (photography and special fx) it does, but in terms of plotting, storyline, acting, directing and so commercial TV seems to push towards the bland.
BBC is an arm of the government, largely paid for by the TV tax. Sometimes that frees it up to put on better TV, but it also frees it up to put on a lot of absolute dreck that thankfully never gets over here, and of course there’s the whole being a propaganda machine problem.
What you’re missing is what the product is. TV shows are NOT the product TV channels sell, WE are the product they sell, TV shows are just there to lure us to watch commercials.