Rainbow Six Siege's game director says he eventually wants his game to go free-to-play. In an interview with PC Gamer, Leroy Athanassoff said that while the idea is popular within the development team, Ubisoft has the final say.
"It's a company decision. I think on the development team we want that at some point We want to be accessible to everyone." That accessibility doesn't just apply to the game's price-tag, however, as Athanassof says that there's work to do before Siege can go free: "you need certain features ready to be a good and successful free-to-play game."
According to Athanassof, the most important of those features is a working solution to smurfing. The practice, which involves setting up a new account to play against less-skilled players, isn't a bannable offence in Siege (although it is in other games) but it's clear that Ubisoft wants to prevent it becoming a bigger problem than it already is. Until they can do that, it's unlikely that they'll want to remove the pre-existing financial barrier from the game.