Sprint spokesperson David Owen told PhoneScoop in an interview:
"I would not count RIM out. RIM keeps reinventing itself. BlackBerry 10, as we've looked at it, has some really good characteristics. We're excited to see what it can do. The challenge is RIM took on everything. They took on the entire gambit: the storefront, the operating system, the manufacturing, and this caused them to be slow in reacting to the changes in the market. We don't think we will see RIM get back to the levels they were two years ago. So we have to figure out where they'll be going forward"
This frankly doesn't surprise me. Sprint has been struggling after it invested so much on getting the iPhone and having those investments not really pay off. That being said the comment in general does seem to have a positive tone to it and good thing too. Carrier support will be crucial to how successful BlackBerry 10 is in the U.S. market.
No one really knows what happens behind closed doors between carriers and manufacturers. Sometimes, carriers want these devices exclusively in order to fully back them.
It would be completely understandable for a struggling carrier, like Sprint, to have seen and liked BlackBerry 10, asked RIM to have one of the two (if not both) devices exclusively and having RIM decline.