There were many factors kaya nag-iba ang music ng chicosci, I think, and one of the most important was that radical ang naging change in taste of music ng members mismo. Another one was that Miggy's voice range did change from when they first started, and how it is now - they had to adjust to that, definitely. Heck, that voice change could be why they don't like playing the older songs (have you guys heard Sting sing lately? I doubt if he can do the old Police stuff - same problem).
As for them not wanting to play the older stuff at times, think of it also as the "rock's revenge" rule. If a band keeps on playing the same thing over and over, di ba magsasawa rin sila? Also, if the song is not part of the album that they are currently trying to sell, hindi rin ba the band would rather play songs from the new album? This feeling is magnified, lalo na kung nag-iba talaga ang musical tastes ng band mismo.
They have certain goals that shaped the new sound, and I think they are still evolving. Some of those goals may not be agreeable to the older fans, and some of those goals may be aimed at getting new fans. But sell-out? I think the ultimate sell-out would be to keep on playing the music that the original fans loved - even if yung puso ng banda, wala na sa music na yun. eh di pinerahan lang nila yung original fans nila, by keeping on doing something na hindi naman sila talaga. yun ang sell-out, yun ang gugustuhin ng major label, kasi patok yung idea na yun pagdating sa pagbenta ng album.
So I think they're not selling out. I think they're doing what they want, and it's not what a lot of people like or expected, but i respect them for doing what they want to do, what they need to do, rather than what other people want them to do. And the ironic thing is, since it's going toward a direction that is a bit more "popular", automatically, iniisip ng tao...SELLOUT!
Oh, the irony.