IoT and blockchain: Are we there yet?

The internet of things (IoT) and blockchain - they should go together like strawberries and cream, right? What could make more sense than a constant stream of data about devices, their state, and their use, combined with a distributed and trustworthy mechanism for anyone to read or say things about the data? The technology's certainly not perfect, but that doesn't seem to be the main barrier to success. Cultural and organizational issues consistently present a bigger challenge, which is hardly surprising when you consider that these IoT/blockchain combos make most sense when deployed across a fairly broad set of stakeholders. Combine evolving technology with a loose federation of often-competing partners and no central point of control: What could possibly go wrong?