The idea is that we will develop such stunning abundance that living costs will be very inexpensive and a basic income will be a manageable cost for the government.
Net of the UBI? Sure. A UBI which is exactly as redistributive as the existing welfare system would reduce taxes (or increase the UBI you receive) by the difference in the administrative costs between the existing welfare system and the UBI.
And that's before the economic benefits of increasing the incentive to work for low and middle income people by not reducing their government transfer payments when they get a job.