I do love the idea of an API-centred Lego-ish software assembly approach, but imagining a future when my entire app solely consists of calls to API's (maybe 100's of them), I worry a bit about wait times due to serial blocking calls (and failover generally), and dependency management at a business level (how do I track when one of them goes out of business or is having some downtime). I guess there will have to be a big industry out of wrapping and managing lower level API's in higher level abstractions (just as we see infrastructure businesses built on Amazon).