I think there may be a way to guarantee a universal basic income with out government.
If we are able to displace labor with capital investment completely, dividends will be paid to those who hold the capital. In the future, one may be able to simply hold proof of stake or similiar financial instruments to gaurantee an income.
The problem would lie in distribution, how does one initially obtain ownership stake in the entities that control the means of production?
In truly competitive environment, even in a world without labor due to automation, all prices should approach continuosly declining costs. In an age of abundance, will we even need income?