Sabbath ran that policy too, iirc... a great work's collective...
As known, I was lucky having "grown up" with Slade, just as I did with ACG, but unlike Status Quo, who were just as much an influence on me, I just never got round to seeing them for some reason or another; again, all those Hammy O gigs, and Wembley at their peak and them just round the corner from me... Much later, I just did not want to see them as the "Frantic Four"... It was them, but not...
I got to the point with them (Quo) that it was just "SingalongaQuo", to coin a Brit expression...
When Slade got their second break they produced some decent rock material and, live, chucked a significant quantity of it in... Slade doing an "unplugged" would be a nice idea; I'd watch it, from a "Far-Far Away", but I would not feel the pull to go, unless they played the Ironworks in Inverness...
There's not a massive amount of stuff I still can be bothered to see, though we (me and daughter) have a re-scheduled Satriani gig to see next year and a Hollywood Vampires gig to see later this year, if it takes place...
I will never see Grand Funk or Foghat, both of which I loved, and Free is just a warm memory of something I could have seen... at least I saw Bad Co early on...