Genre classifications are equal points fickle and pointless, but classifying Rush as prog would depend on one's definition of prog (obviously). Certainly, no one would put them among the symphonic, keyboard driven groups like Genesis or Yes or the eclectic, experimental, jazzy groups like Gentle Giant or King Crimson, but as far as being placed on Progarchives overall, they certainly have a place somewhere in the heavy rock/metal categories. Personally, I tend to use a pretty strict definition of prog that would probably exclude Rush, but that has nothing to do with quality. Van Der Graaf Generator is my favorite group and I don't consider them to be prog either.
As for the original OP, I tend to be skeptical of any group that carries on for decades. After a certain point, it's time to hang it up, form a new group that goes in a completely different direction. Play with new people. Anything but pump out roughly the same music endlessly (whether this applies to Rush, I have no idea).