Hi!
Current legislations do not support the licensing of individual facts, only of databases as a whole, and only in some countries. What you are
Added to that, even if it *were* possible to copyright facts, I think using restrictive license (and make no mistake, any license that requires people to do specific things in exchange for data access *is* restrictive) makes a lot of trouble for any people using the data. This is especially true for data that is meant for automatic processing - you will have to add code to track licenses for each data unit, figure out how exactly to comply with the license (which would probably require professional help, always expensive), track license-contaminated data throughout the mixed databases, verify all outputs to ensure only properly-licensed data goes out... It presents so much trouble many people would just not bother with it. It would hinder exactly the thing opens source excels at - creating community of people building on each other's work by means of incremental contribution and wide participation. Want to create cool a visualization based on Wikidata? Talk to a lawyer first. Want kickstart your research exploration using Wikidata facts? To the lawyer you go. Want to write an article on, say, gender balance in science over the ages and places, and feature Wikidata facts as an example? Where's that lawyer's email again? You get the picture, I hope. How many people would decide "well, it would be cool but I have no time and resource to figure out all the license issues" and not do the next cool thing they could do? Is it something we really want to happen?
And all that trouble to no benefit to anyone - there's absolutely no threat of Wikidata database being taken over and somehow subverted by "enterprises", whatever that nebulous term means. In fact, if Google example shows us anything, it's that "enterprises" are not very good at it and don't really want it. Would they benefit from the free and open data? Of course they would, as would everybody. The world - including everybody, including "enterprises" - benefited enormously from free and open participatory culture, be it open source software or free data. It is a *good thing*, not something to be afraid of!
Wikidata data is meant for free use and reuse. Let's not erect artificial barriers to it out of misguided fear to somehow benefit somebody "wrong".