I know what the exchanges charge for data access, and even if you pay it is in an antiquated format.
Tradier has been providing equity and option tick data for free for years in a clean RESTful API with the capability of websockets and streaming. So thats the answer to your question of who.
Thats part of their business model. I have not used their data but I can tell you that all tick data is not created equally.
We are unlikely to ever see CDS data for free since individuals cannot trade them as most retail investors are not Eligible Contract Participant. Some brokerages give away data to get people to trade with them so there its about customer acquisition.
Tradier has been providing equity and option tick data for free for years in a clean RESTful API with the capability of websockets and streaming. So thats the answer to your question of who.
Like I said, in this town we call it disruption.