I agree that Kiss in the last few years has been really crap and as you said killed by greed and mass merchandising... but I think the "neverending farewell tour" that everyone keeps talking about is a bit unfair, at this point anyway. The Farewell Tour was in 2000/2001 and didn't even actually go as long as it was supposed to, they never got to finish it off with Europe and the 4 New York shows they planned because Ace left the band so their last shows were the Australian tour in early 2001. And now this Symphony Show is just as one off show and Paul has called it their "fitting farewell".
So time will only tell if they continue as a live band after this concert but at this point the farewell tour has actually gone shorter than planned and this is supposed to be their final show now. However that is according to Paul, and Gene has said differently a few times. I think with the problems the band is having though it will be the end of Kiss as a live band... Ace doesn't wanna play for them anymore and Peter is too old and would never rejoin for more than a one-off like this. And Gene and Paul would never have a non-makeup Kiss happening again as they are so obsessed with the original lineup nostalgia thing these days.
And without the makeup, Kiss were still not just an average rock band in my opinion. They still had a special vibe surrounding them that no other bands had, and wrote BETTER music with better musicians than they did in the makeup days. Vinnie Vincent, Eric Carr and Bruce Kulick were the best things that ever happened to Kiss.