Maybe because, sometimes, people sit down, loom at themselves and think "are we the same band that we used to be"?Very stupid way of thinking imo. That goes for any band in the world, why should they have to start another new project/band just because they want to progress/change musically?
I mean a Black Metal band could just totally change and write a Pop album, should they have to start from scratch with a new name just because the music doesnt sound the same as the last record and some people will not like the music? That sounds stupid. If anyone writes music they like they shouldn't have to form a new band just because it sounds different lol. I know many musicians do create side-projects though for their other musical visions, but it all depends on what artist it is. Some already have a progressive sound from the start like Devin Townsend and just jumps genre's without a problem whatsoever. I guess it depends on intent also, if it's just some music they want to write and release but don't plan on performing it live or anything, then obviously it should be a side project. That isn't the case with In Flames though. Regardless of how bad or good people think it is, the reality is that this is what In Flames wants to do at the moment. I would also love for them to write a more aggressive album but if they don't want to do it, why should they force it just because?
Maybe because they have lost one part of the triumvirate, one part that was really important. Maybe because there are only two members left and they don't seem to know what they really want to do with their music.
I don't know. There are many reasons.
By the way, Steve Harris British Lion is playing live, Bruce Dickinson is about to release a new album that he is going to play live. Chris's Cornell had a solo career apart from Soundgarden, Bjorn Strid has The Night Flight Orchestra... So maybe some people just think that some music does not fit their bands and still they thinknseriously of their alternate projects.
I really think that there are a lot of musicians proving your point wrong. But that's my thought. As I think that calling a thought stupid is not the best way to discuss shit. But that's up to you.