One might argue that a majority can not decide anything since it's not an agent, nor is the relative amount of people who share a specific opinion somehow relevant in most of contemporary politics.

Also taxation is not a one way route as it might backfire through tax avoidance or just collective time re-allocation.

I'd bet there is no single agent on any developed country either powerful enough or knowledgeable enough to implement the UBI as it will most likely require massive legal and political changes.

So I guess it's pretty obvious why no one implemented the UBI yet.

Edit: never mind. I guess I miss understood you. Sorry.^^