From a creditable source >
"Its my opinion that the vast majority (if not all) of the albums lyrics were penned by Bon, its painfully obvious how the song writing changed after BIB , no more catchy ditties about the ups and downs of a rock n roll singers life and observations, just repetitive nonsensical blathering on, even the basic structure and sound of the band changed .Indeed I feel the heart and soul of the band died that cold Feb day in 1980 with Bon.
The ever present notebook that Bon carried with him was not found among his belongings in his ransacked flat, and even Bons mother was quoted as saying "those were Rons words" on BIB (she didn't call him Bon) , the Young brothers claim to have enclosed his lyric note book in his belongings returned to Australia which his mom said didn't happen.... I have discovered over the last 20 yrs or so that a lot of older fans of the Bon era AC-DC share my thoughts about Bons work being stolen , Brian got writing credits on BIB and the next few albums until the Youngs decided to take that over as well (he never wrote a song before AC_DC), not that either one of them can write decent lyrics! My feeling are that he was given the writing credits to keep his mouth shut..." sing this and keep your mouth shut" and you will become rich. When it became apparent that he was not a writer or musician( like Bon) the paranoid Youngs took away his writing credits. I has been speculated many times that Malcolm wanted to fire Brian in the late 80's early 90's, my guess is it didn't happen because Brian would spill the beans on the theft of Bons work. Even the record company brass in the US wanted Bon gone before the HTH album, he didn't live up to their "standards" somehow and they felt the band had more earning potential with a new lad up front. A lot of this background info as well as the list of unknowns surrounding Bon's death has really caused me to rethink his demise and question if his death was really a death by his own misadventure ...at the very least the Young's are guilty of the theft of Bon's material and future royalty earnings from his family and a fraud on all of their fans ....if his death was not completely accidental then they are certainly involved in that to some degree as well..."
IOW - How many of AC/DC's subsequenct albums came close to BIB's success? None as we all know. In all the songs they've recorded don't you think (1) one would at least approach YOU SHOOK ME ALL NIGHT LONG? Of course. Again none have. ^That should tell you all you need to know. Bon was known to keep a notebook w/ him at all times (unless he was drinking) & he told his mother a few days before his death in a phone call "I have at least 10 great songs ready to be recorded". His infamous notebook was never found. Case closed.