Lightning network is now testing on main net with number of channels growing dramatically.  This will solve the scalability problem soon.

As for adoption, it comes after the scalability issue. In the past we have seen some services no longer accept bitcoin payment be cause of fee and confirmation time, but when that problem is solved, nothing can stop bitcoin anymore.

The government can ban bitcoin, in fact, we are seeing that battle right now. If they really want to ban it and go really harsh on cryptocurrencies, we will see another bloom in the anonymous-type coins for sure, and maybe bitcoin can adopt some more privacy technologies like those of Zcash or Monero