How many mainsteam bands really have been relevant in the last 30 years? They've all been out there on greatest hits tours for the most part. For the last 15 years, no one has been able to sell a record thanks to Napster and the beginning of illegal downloads. The only bands who are financially viable are the ones that are grandfathered in, so to speak, and were popular before MP3's. Sure the Stones can sell out arenas, McCartney can sell out arenas, U2 can sell out arenas. After that the list starts to get pretty thin. AC/DC can sell out arenas because they have been in one record/one tour every 8-9 years for the past 20 years or so, so they have pent up demand.
To get back to the original assertion that Kiss hasn't been relevant in over 3 decades is a bit of a stretch. The reality is that they haven't been relevant since the reunion tours of the late 90's. So, I would go with around 15 years. But for me, I love their back catalog and they have plenty of great songs to fill the needs of a pin. They also have plenty of great themes and gimmicks for a pin. I definitely picture a toy that spits blood in some sort of acrylic case, where it just sort of cycles through so that it can happen over and over again. I definitely picture a smoking Ace Frehley guitar for the match sequence.