Maybe?
I check this site, they show if the RTP always change on every games, some of them are actually more than 100%, which mean people are making profit from that game, no?
Maybe it could happen if the casinos are charity homes but they are not, so therefore, it will never happen, because they are just like every other business venture which needs to stay in profits to continue running the daily affairs of the business. A zero house edge makes them vulnerable and that includes a 100% RTP too. So OP, stop dreaming and face the reality.
I don't think having 100% RTP can be called as charity because that means you and the casino have the same chance to win, it will completely depend on luck which one gonna making money in the long run.