Sure he shoulders most of the blame. The FO opened their wallet and directred him to get exciting "sexy" players and Theo implemented that philosophy very poorly. He spent maga bucks on the likes of Lackey, Crawford and a first baseman with a bum shoulder. If he had gone for Cliff Lee and Matt Holliday the story of the last few years would have been very different the last few years in Boston. He executed the philosophy very poorly. The owners are interested in revenue and their concerns were well founded-- TV ratings had been slipping. Theo brought in the wrong guys, squandered their huge budget and left them with an enormously expensive but totally suckass team with no payroll flexibility. So, yes, he built this pile of garbage.
As for Francona, I love the guy, but he has a bit of an ax to grind.