Big difference is that Bitcoin has all the right conditions for a bubble pop. If someone did a 51% attack, this would cause people to lose trust in the currency, everyone would cash out, creating a bank run, which would be a self-accelerating process that drives the price even lower. So even if the network recovered the next day, it would take a long long time to rebuild that trust.

Whereas with the internet, if someone is able to knock out critical infrastructure one day, engineers would figure out a way to fix/reroute it, get it working a few days later, and everyone would happily log back on as soon as it's working. Although maybe they would throw out their "smart" coffee machines and etc.