DAC/DAPPs/DAS all the way.
Will improve transparency if they choose to use any specific chain to register transations and code them effectively.
It seems likely Apple, Google and Yahoo have done their sums/due diligence and realised there is nothing they can launch that can compete with BTC. Why? essentially BTC tech forces you to relinquish control if you are to be trusted. This is antithetical to old corporations system, where State prescribed corporations redistribute profits to shareholders for good organization of capital (not inherently wrong, just not as efficient as it could be). The DAC/BTC model cuts out a lot of the centralized corp structure and lets people join ad hoc or leave. Imagine for a moment that to make money Apple had to give its patents away.
Even if they built a hash farm to take over all they would have is a worthless coins as every forks or uses an algo resistant to their farms tech.
It's the nature of the break though of the byzantie generals problem that basically makes old style 19th/20th centry corps model reduced. This becomes even more compelling with the multisig for contracts etc.