////It depends, josepp, on what you mean by "Bubblegum Rock", but "Classic Bubblegum" of the Ohio Express/1910 Fruitgum Company variety used straight major and minor chords and *avoided* major 7ths. The "SECRET" of Bubblegum music was the pulsating bass-all eighth notes, on the chord fundamental, while a cheesy Farfisa organ played something like "Bah Bah Bubah-Bah Bah Bubah" and the guitar avoided leads of any kind./////

My statement is a total stereotype meant to give the reader the idea of how a flatted 7th differs from a major 7th. Like any other genre, no one statement can cover all of bubblegm and be right all the time. And your statement is proof. There is no farfisa in "Sugar Sugar" that I can remember. It used a vibraphone. There was no keyboard at all in "Yummy Yummy Yummy" and no particular straight-8 beat that I recall. "Green Tambourine" also does not follow your formula nor does "Finders Keepers" or "Captain Groovy and His Bubblegum Army" (which has a manic rock guitar lead at the end).

/////He starts on a B, then jumps to the D7, which is the fifth(dominant) in the key of G, and resolves to G.

Then he jumps to Bb which is the 5th (dominant) in Eb, and resolves to Eb.////

5ths love to resolve. In jazz, we are taught to virtually always go to the 5th before resolving. I can't imagine it wouldn't be true in other genres of music popular in the US. And it is very musical sounding.