Massadoption will never happen.
Though Bitcoin was created as alternative which I think make mass adoption somehow impossible/hard to achieve but there is always a solution to very problem.
Two many barriers, the first one being the lack of ergonomic of the user experience.
This issue of been discussed several time but i can assure you if all governments around the world supported digital currency a solution will be created, we have good thinking experienced Dev within the system.
Private key are not user-friendly, fees are higher than other payment services and so on...
The last time i checked the TX fee of cryptocurrency is not higher than payment services if you know how to do it professionally and if private keys are not friendly to you, you can make use of the custodial wallet but the fee is ridiculous sometimes.
Yes, as you mentioned, there are solutions.
But once again, we are talking about your average neighbour, they are not easy-to-use.
Of course, you could use Coinbase, which makes everything easy. But what's the point to use crypto? Might as well use Paypal...