I've also heard that the spysat guys had learned lessons that would've been very useful for the Hubble developers. The question is whether they were simply unwilling to share the lessons learned or were unable to do so due to securty restrictions. I strongly believe the latter is the more likely explaination.

Spy satellites are deep in the "black world" where real information never sees the light of day. The technology is well above Top Secret into the areas of Special Compartmented Information (SCI). By contrast, the Hubble is unclassified. Any technology shared between Keyhole and Hubble would become public knowledge and could've been used to do things like improve the capabilities of Russian spy satellites. That wasn't going to be allowed to happen.