Trying to figure out wtf is going on regarding this band is like trying to nail jello to a tree.
This may sound odd/not make any sense and I'm sorry in advance. I don't believe Zayn left b/c he wanted a solo career. His solo project (as well as all of their side projects) were going to happen. Zayn left because he didn't want to be a part of 1D anymore for many reasons (stressful/anxiety induced schdule/negative media attn/mngmnt quarrels/kiddie brand). It is depressing doing something you don't love even though you're with people you love. Brand v. Band. Loves the boys, hates the brand.