What happened to Rush?! (the band)?

I do admit I liked their older stuff a lot more. (Power windows, Caress of steel, moving pictures, fly by night etc etc. But whats with the new stuff, I dont really like how its getting a heavier feel, I liked to synthesized light rock in power windows way more than snakes and arrows, I still like the newer stuff. But what happened? If moving pictures was their most successful album ever then why are they grower away from that sound. After all its the only reason I got into rush. By the way I mean no disrespect to Rush. (Pretty much the only band I listen to and cover, and any of there music regardless is amazing.) Also how do you think they achieved such greatness?