I never listened to Alkaline Trio (seen them play a song on Late Night, but that's it) so I can't make any comments about them.

However, I'll say this... there's a difference between changing music style and "selling-out." "Selling-out" is when you change everything around because the label is on your back about it... like you record your thing... they don't want it... they say do it this way instead or we'll drop you 'cause we want you to do what we think is hot and will make more record sales.. and you comply (reluctantly... nonetheless, comply).

For example, when Radiohead (slighty) evolved into a different sound... that is not regarded as "selling-out." They simply came to what they were working on from the beginning really... (just listen to OK Computer)... and with both Kid A sessions... they were doing what they wanted. In fact, it scared the label.

I think bands should do what they want and be respected for it. There's always way too much talk about the "selling-out" thing.

It's almost as if a band's making a little money, they get hated, which isn't a fair thing at all.

The band Low got a little louder on the recent album than their usual minimalistic clean electric guitar sound shoegazing slowcore. And, I bet they're a little hated now. Which I shouldn't spend time thinking about (I should just care that I still like them and that be that)... but this just helps make the point.

I'm not even on a label and I make music from no-wave noise to acoustic folk and play in band that does early-like psychedelic pop. Am I a "sell-out".. no, I'm not even signed.

Hopefully, all made sense...
At the end of day... listen to what you like to listen to (and even listen to stuff you never heard... to discover possible wonderful takes on sounds and enrich your soul)