You don't know anything about marketing. If it's exclusive to Verizon, maybe Google doesn't care about profits for all we know. After all, Google has made it's billions off ads. Google wants to build it's phone brand by developing a sound base of customers.
As a company, you want to control the customers experience with your product. You don't want to put a great phone on a crappy network like Sprint where you might experience horrible battery life, throttled 4G, or spotty connectivity. Totally goes against Google touting great battery life when the Sprint network actually kills your battery. First thing a customer will blame is the phone, not the carrier. Some people aren't that phone savvy, hence the iPhone.
If you want to be successful as a company, you have to control the experience of your customers. For example, I can rent a movie from the Play Store. Google will give me a refund for the rental if I decide to buy the actual movie through them. People are shocked when I tell them I've done this repeatedly. I can't get my money back after watching a rental through Amazon or the Apple app store so I can actually buy the movie. My customer experience with Google is solidified.
I was pissed when I couldn't get the HTC M8 on Sprint in silver. Silver was exclusive to Verizon. Definitely considered switching carriers and some people will switch to get what they want. It's a good tactic.