What do high-end speakers realistically provide that mid-priced speakers do not?

I have an "untrained" ear and have limited experience listening to systems featuring speakers above $5,000 per pair (obviously the entire system's budget would be way higher, but I'm talking about systems built on a L and R that exceeds $5k/pair and the rest of the system being of equal or better quality).

In my research I did listen to what I consider mid-price speakers (KEF R3 Meta, Bowers and Wilkins 706, etc.) and I can't imagine it sounding better!

So, those of you fortunate enough to listen to truly high-end speakers for long periods, what do high-end speakers provide that mid-price speakers don't? Are the differences drastic or is it basically splitting hairs? Do you mentally divide high-end speakers into tiers (high-end vs. super high-end) and what do you expect from each of those tiers?