Don't think I would agree with that, top 2, gap to 3, gap to 4-8 gap, 9-15 gap 16-20, its like a salami sandwich!
TV revenues have helped lower clubs, but compared with top 6 finances its still peanuts.
Liverpool won their 18 of the 19 league titles pre-PL days!
I would agree that the top 2 maybe 3 teams are much stronger than 4-8 etc., but that's not indicative of the PL as a whole, with the exception of United (of course) and possibly West Ham, Brentford and Everton (for differing reasons) most other PL clubs are where they would expect to be on their strengths.