Back just a few years ago you could do a little search and find all kinds of casinos giving away cash, today is it different and the totally free bonuses are disappearing quickly. As the move to push mobile casinos played into the gaming industry the security checks were a bit more difficult on detecting fraud users. This left the casinos no choice but to only offer deposit bonuses on mobile users. I am sure the complaints came in when users would see offers for cash without deposit and yet they were not receiving them. This has lead to many just offering larger deals for new users and doing away with the no deposit type offers.
Will this change in the future? Sure it is possible that they software will get updated to detect more. The biggest problem how they do now is by ips which can bounce around if you are roaming and the other was by machine address. They could require proof of id and address before issuing money, I just highly doubt they will at least for quite awhile. When your lucky enough to pick up some cash for free, grab it as the next time you look it could be gone.