Right, I understand the bit about getting through more books, but why? There are an unreadable number of mind-blowingly brilliant novels out there and basically no reason to read any them except to enjoy oneself.
If I am enjoying a book, I can’t imagine having the urge to finish it faster. Or slower. What could possibly be gained?
Edit: also, just some unsolicited thoughts on your struggle to complete a Scanner Darkly. IIRC, A Scanner Darkly is a fairly average length novel, meaning you might expect to finish it in ~10 hours of reading. My personal experience is that it's best to enjoy a novel within a relatively limited time frame (say a couple of weeks) so that the various characters and plot lines stay fresh in your head.
If I were in your situation, I would probably question whether:
A) If I actually like the book. If you are even a quarter of the way through a book and don't like it, nothing wrong with picking up something else. As I mention above, books are for enjoyment. If you don't enjoy it, what's the point?
B) If I perhaps don't have time to read a novel now. Sure, nothing wrong with starting a movie, pausing for dinner and then finishing it afterwards. But there are limits. You wouldn't want to split a 2 hour film into a dozen ten-minute segments. And I would argue, wouldn't you want to split a 10 hour novel into a 60 ten-minute segments either. Just not a good reading experience. Nothing wrong with putting the book on hold and coming back in a few weeks once your schedule has calmed a little.