It’s about a comparison of the top heads only with the exact same reso, which was tuned at the factory; all other variables being equal.
But your absolutely right, the reso is key to good tone. He will have 2 more videos coming that will cover other variables like the reso and bass drum; which he didn’t touch. The point of the first 2 videos was this is factory new from the box and this is quick and dirty new head change.
He has just started to “tune” them; you got to wait till the end to get the whole this is my sound process.