We have to decide we want to do it before we can figure out how to do it.
Agreed. But that's "should" language, not "can" language.
There is a definitive plan to live in a stateless classless moneyless society, it's called socialism.
The last time something called socialism got widespread, it too succumbed to horrible corruption.
Focusing on how long and complicated the path could be is a great way to keep people disinterested in making any change whatsoever.
Ignoring how long and complicated the path to aircraft could be is a great way to get people jumping off buildings with cardboard wings.
I'm not saying you need to hide that part of it, but the way to inspire change is by keeping focus on what the goal is, and making it seem like it's possible because it is.
The Incan economy isn't going to painlessly scale to a globalized society. Pretending that it's a rational alternative just makes you look foolish, which does more to hinder progress than soberly acknowledging the difficulty of the problem.
money is extremely vulnerable to corruption
Yes. Every system of resource and labor allocation is vulnerable to corruption. Some people are greedy, and no matter what system you devise to allocate resources and labor duties, some people will figure out how to manipulate it for personal advantage.