I don't see any reason to think MDVN could not have licensed ex-US only. They would be far from the first to have leverage to sign such a deal. Alternatively, if for some reason you're right and MDV-3100 was unpartnerable unless they licensed WW only, the early data was compelling enough, they should have held. If MDV-3100 failed, the stock would have been going to liquidation value either way. Licensing out WW was nice but will turn out to be somewhat value degrading. I always prefer to invest in companies that retain all rights or most. Just the opinion of a pipe dream investor.
P.S. Cougar was acquired for $1b not $894m and your comparison is a bit biased since Cougar sold out pre pivotal data. It was a risk averse but rational decision at the time, since of course failure and the stock would have gone to zero.