Bon Scott was a card-carrying fan of Alex Harvey, he was his role model.
Johnny Rotten/Lydon was more third generation, he patterned himself (admittedly so) after Gary Holton of the Heavy Metal Kids and emulated him,
but Holton in turn was of course another great fan of Alex Harvey! There was a good portion of Brit Vaudeville in Alex Harvey's act, you're absolutely right. Harvey was born 1935, he simply came from another era and had other influences than most 70ies hard rockers who were ten to fifteen years younger than him (Gary Holton was born 1952, yet died - overdose - already only three years later than Harvey who was 47 when he passed away in 1982 due to a heart attack, tragically one day before his birthday).