Imagine when we are at 20% in a few years!
20% won't come easy, but the growth should be exponential.
So even though 20% is still far, 40% will come much much faster afterwards.
The problem is, most people will only adopt new technologies... if it is more convenient and more user-friendly.
Actually the problem is that people will only adopt technologies
they understand.
You are both right and both wrong. People don't understand nor care how Visa works, but it's extremely user friendly (and yes, many don't use even Visa...)
So the wallets have to be even more user friendly and fool proof. Then... even those who rick and come use Bitcoin get surprised by the volatility and the tx fees.
For the merchants it may be easier, they just need a payment processor that accepts Bitcoin and transfers them fiat into the bank account (please don't expect all merchants install bitcoin software for payments and also handle tax for bitcoin vs fiat), so maybe a good first step would be to get more known payment processors accept Bitcoin (and maybe also don't make the prices 10% bigger if paid in BTC).
If so, average Joe will know the bitcoin is an investment vehicle and he also can pay easily with it (he will see it as payment option everywhere he pays). It may make him curious enough to try it.