I agree on the rep, is like if word of mouth had put the album in the dark. I would say absolutely ignorance, in the sense of being absolutely overlooked without even bother to check, and that started the chain reaction.
When I started with JP I did it with SFV and DFOTF, needless to say crazy about the band I started to build the back collection. I remember when I found both "Rockarolla" and SOD on vinyl (made in Spain) with the original artwork. And I do remember that even if the debut wasn't remotely like their mid-80s albums was really cool rock (and still is). When the song 'Rocakrolla' started was so damn catchy that stuck like gum in a shoe. It's still one of my faves throughout the years (along with 'Cheater' and 'One For The Road'), the album was also pretty prog at moments. I guess the band in its inception was tossing the coin if they wanted to follow Deep Purple onto Yes, or Deep Purple into Black Sabbath. I guess the lately happened and we have the Metal Gods.
Some 5-6 years ago I finally found the reissues on CD of both albums (property of Gull Records) with the original artwork too, and I know that now 30 years after its release "Rockarolla" still as good as it was on its day...and maybe better