Interesting story, but I'm always at a loss when any article mentions that the DMD was the "Peak years" or "Peak Era" of pinball. Nowhere near it !
1991-1993 had 75 games from all manufacturers.
1977-1977 had 333 games from all manufacturers.
Based on volume, 1991-1993 would not be in the "top 10" of "Peak Years" of pinball.
Eight Ball and Flash sold a combined 38,000 units. KISS and Playboy sold a combined 35,000 units and both licenses were the biggest of the 70's.
you could apply the logic of licensed VS non licensed, but I would argue that the licenses back in the golden age of pinball were not as important as today, because of the fact pinball was far more popular in the 70's. you could put anything on a playfield and backglass and people would play it in the sixties - eighties.