They have to have rewards because the crapitalusts currently oppressing the masses require money for food, clothing, and shelter.
The same reason that the transformation from debt slavery to freedom has to occur for all of us at once.
The crapitalusts have bombed almost all of even the experiments back into submission.
https://listverse.com/2016/06/29/10-instances-of-anarchist-societies-that-actually-worked/