What's Bitcoin missing in technological or infrastructure terms that's holding it back? I'd wager nothing.
For the vast majority of people, Bitcoin doesn't solve anything - in fact, 'is slightly incomprehensible and weird' and so is actvely disuassive of its use.
A cross between ease-of-use and simple knowledge that it exists.
As one example, I know of digital artists who sell their work over the internet, but have trouble receiving payments because paypal doesn't like their platform being used for porn. Bitcoin (& etc) would be the perfect solution, but it doesn't ever seem to even cross their minds as a possibility.
The technological solution to the slight incomprehensibility is a huge part of what holds back adoption.
Also, regulatory issues are considerable for a certain class of user that would probably like to take advantage of e.g. 1000x gainz.
Yet...?
It's a solution wherein principally the currently-invested are the only stakeholders hungry for a problem to solve.