As I read it, that analysis (about Mozilla losing money from a Yahoo sale) doesn't factor in the $1 billion payment Mozilla would be owed if they walk away, and is based on the assumption that Mozilla won't be able to make another search deal to replace its revenue with Yahoo. It's probably true that they can't replace 100% of it, but if they partially replace it, and then make up for the shortfall with that billion, that probably takes care of them for many years.
Another possible scenario: Mozilla pockets $1B, several months later Yahoo goes bust and then they're free to do whatever they want because Yahoo can't perform any more.
Long term quite probably yes, but if they manage that money wisely and concentrate on their core product rather than on all kinds of funky (and costly) stuff it could last for a long time.
I had a deal with a big provider in NL to pay a fixed fee every month, when they backed out I forced them to pay the full amount over the duration of the contract in one go.
Not saying that will always work, but it did work for me (it wasn't a billion though (obviously), but a few hundred K).
