The chance you can see currently of adoption of Bitcoins, this will be the same in the future also.
I mean why government will adopt something which they cannot control or impose tax on it? So in future also the scenarios wont change according to me.
Governments can't control bitcoin, but they do manage to control bitcoin users by regulation. Then from there the government also succeeded with its tax rules against bitcoin users where it made the most sense to apply when the government did not prohibit trading or mining. Regulations between countries regarding bitcoin of course vary and the same applies to tax rules. India has a higher tax percentage than my country, but bitcoin is still not legal as a means of payment. That's the problem, they want profit while they don't support freedom and adoption which can somehow be construed as bullshit.
Moreover we are also happy by maintaining our privacy with Bitcoins. So I guess there is no need of adopting the Bitcoins publicly.
My opinions on this might be differ, but this is what I think of.
Even without adoption and legality, you can own bitcoins with a good level of privacy which the P2P marketplace will help. Decentralized exchanges like Bisq can also help you maintain your privacy, these are exchanges that do not require you to register. Then later if you want to remove traces or obscure transaction traces, the mixer can also be used as a follow-up effort so that your privacy can be better.