This brings in a new point. Can ISPs block or delay a node or miner traffic?
ISPs can traffic non-Tor and non-VPN connected users who will run their own node. Not sure why should an ISP ban a node, since bitcoin is neither illegal or legal in most countries. Should I assume that you mean that governments will illegalize it? What government succeeded on stopping a p2p network? None. As for the mining traffic: You just need to be internet connected in order to broadcast it. This can be done with a lot of ways such as with VPN and Tor if you don't want to be known to your ISP.
Yes but government banning on/off ramps and illegalising the trade can and will affect the ecosystem. Pushing the whole system underground is the answer but at what cost? can it survive forever underground?
Assuming that governments will make it illegal, because they've tried and failed several times, I'll respond you with a nice example that has been discussed a gazillion times: Did the BitTorrent survive? It's been accused by governments since the majority of its users, use it for illegal purposes. That's the same with Bitcoin, they won't ban the protocol, but its use. They will not succeed, because no one ever succeeded on banning a p2p network, especially that big.
I believe that they should start adapting with it, at least those that haven't done it yet.