There's also the simple fact that, just because a band has their original lineup doesn't mean there's any sort of implicate superiority. Sometimes a lineup change is a good and healthy choice. I'm very clear on my stance that I'd probably enjoy the band a lot more if Larry called it a day, already. Possibly Adam as well, but I'm less passionate about that viewpoint.
If you look at bands like the E Street Band, yes, they've had different lineups and yes, Bruce and they parted ways for a short time. Does that make the material they're making together, now, of any less quality? Does it make their tours any less enjoyable or successful? And of course, there's all the solo artists out there still producing albums and still touring, too.
Pure and simple, U2 are a great and very popular band, but they're not the only one and I'm sure there are forums for other bands out there having similar conversations all the time. You can't ignore one other band, VERY similar to U2, who may not still have the same lineup, but who I do think are enjoying far more success and relevancy today and that's Bon Jovi. You don't have to like them, but they have managed to wrangle in a whole new fan base in the last decade, thanks to their change in sound. I'm not sure they've ever been bigger.