1.) POW hard fork - which would seem to me to result in a low hash power altcoin since BTC will be already in play at Coinbase, Gemini, Bitpay... based on their public statements of following the majority hash power or being actual NYA signatories.
You seem a little fixated on absolute hashrate numbers. Remember that if the PoW changed, the hash function is inherently different, and so comparing SHA256 hashrate with CuckooCycle hashrate is pretty meaningless.
You're also forgetting that PoW change will see Bitcoin mining explode in popularity, so the actual purpose of the hashing will be far better satisfied with such an unavoidably more decentralised hashrate.
You forget too that Coinbase and Bitpay are not the only providers of their respective services. And in fact, the recent news about Atomic swap transactions with BTC/LTC trading pairs is a paradigm shift in the making when it comes to cryptocurrency exchanges. Sure, Coinbase could provide it, but what would be the point in having a centralised point of trust when atomic swaps transcend the need? Who's going to trust Coinbase after all this strongarming anyway?
You should stop forgetting things
