I knew what you meant (how you thought Welch was cool too etc.) so sure, I see what you're saying
though I gotta agree with ChiliD to a degree here as well in that yes, there is the "unknown factor" etc. (as Chili describes above) and maybe ticket prices for concerts weren't as much back then as they are/seem to be these days (I personally wouldn't know as I hadn't seen FM or any live band for that matter until 1987), BUT assuming tix were around the same "amount of money" back then (and the prices have just simply risen with inflation etc.), "I" personally would find out all I could about a band I would fork out how many bucks to go and see in concert before I went to make sure (or, as sure as possible anyways...) that there were no "disappointments" (as such) in store for me such as the type that you unfortunately encountered.
I realize there are many people that can just go to a concert in a willy nilly, "general" way etc. as that is obviously what "touring" is all about, to get those at the show that are unfamiliar with the records to go and buy them. However, and without breaking out the violins, I, as well as other blue collar folk I know certainly am not (and will likely never be...) in the financial position to just say "oh (so & so) is playing in town tonight and it cost $100 per ticket, well, we don't know much about what's going on with them but let's go cash our paychecks, forget the bills this week and go the show anyways". I sure would love to be in such a position like tose "general" concert goers but if it was costing me a lot of money, I'd want to find out what I could about the artist before buying a ticket (or at least before I go to the show), like when you go and buy a car, you don't just close your eyes spin around a few times in the show room and whichever car your pointing at when you open your eyes is the car you'll buy, you'd want to look in to things first (obviously buying concert ticks is a much smaller situation in comparison, I'm just giving an example that I'm sure many here can relate to).
I'm not saying "you were wrong" for doing what you did (or didn't do as the case may be) as I also realize that there were not as many resources back then as their are now (internet, etc.) but I would've at least gone to look at the records (by the artists I was going to go and see in concert) in the record store to check and see what the latest lineup was or whatever (OK, cue TITN example, Lindsey on album, not on tour, so I'd try and double check it by picking up whatever mags were around back then etc. as in the case of TITN, I'm most certain that LB's departure and the addition of Burnette/Vito was widely covered). It's like "I" personally don't watch C-SPAN etc., but I'm aware of the fighting going on with Saddam etc. same kinda deal (but obviously on a much smaller scale once again). I guess I'd feel better if I went to a show and was disappointed with it that at least I could walk away knowing that I tried to investigate it before hand, I wouldn't always think later on if I was strapped for cash "gee, if I had only looked around and saw that (so & so) have left the band and that they were replaced by people with a much different musical background and they are doing a different kind of music now then I would've reconsidered going and I would have been able to save that money for now".
Well, it's JMHO and I'm glad that you do enjoy Welch's work etc. as well (as I knew you did/do). I guess I needed to grow up in the 60's to appreciate what things were like and why things turned out that way for you at the show, I'm sure you had good reason to "think the way you did" with not being used to personnel changes in bands etc. like you were saying I've just noticed above.
John