I hope everyone is ready for it, because it's going to be the biggest test in your HODLING abilities, and resolve.
What would transpire is the biggest socio-political/socio-psychological attack that the community would ever see, and it would involve state-level actors/governments.
Prepare yourselves. It's coming.
I do expect some action from the authorities, in case the (crypto) market cap crosses the $1 trillion level. Whether you guys like it or not, Bitcoin has become a major rival for the fiat currencies. In countries where the national currency is heavily manipulated (China and Iran for example), there is enough evidence available to conclude that at least some of the citizens are using Bitcoin as a store of value. Now this goes against the government plans to have a complete monopoly on the savings of its citizens. Even in cases where the national currency is not manipulated, Bitcoin is attractive due to its immunity from inflation.
It will be foolish to believe that the government will just sit back and watch the show, when the national currencies take the hit. The tax revenues are going to get affected and the entire apparatus will feel the impact. So at some point, they will be forced to initiate action against the cryptocurrencies.