It is hard to believe that NBC actually expected Leno at 10 to fail in order to push Conan out.
I see all the speculation is that Conan will leave and that Leno will come back to the Tonight Show. I predict that this is wrong. I know all these stories say that NBC is likely to negotiate a settlement with Conan and move on.
After the backlash with the whole Letterman thing, I don't think Leno wants to go back to the Tonight Show with this toxic an environment. People will be hating on him for this. The Tonight Show ratings will not improve much, if at all, with Leno back there. Bad lead-ins and audiences having moved on have changed things from when he left.
Somehow, NBC will figure out some way to accommodate Conan and Leno and work this out. I predict something where Leno has a show that runs during the weekend or just not every day during the week.
I prefer Conan, but I have some sympathy for Leno. He was forced out of the Tonight Show and agreed to it despite not wanting really to retire. If he does agree to come back to the Tonight Show, then I do lose all sympathy for him.