Nobody owns their data. They just scrape the internet, or pirate massive troves of books. Just forcing companies to get a license to all the data they use, let alone an open license, would be a massive impediment to the development of open models.
It is definitely doable to get openly licensed data, you just have to do it via voluntary participation of crowdsourced data acquisition programs. For example the RNNoise model was retrained from such crowdsourced data.
