Unreal has limited traction on mobile, which is now >50% of the gaming market. It's likely one of the reasons Unity thinks they can get away with this. The last number I saw had Unity above 50% share with Unreal under 15%.

It's difficult to champion high end features for your engine but keep it suitable for low end smart phones. Epic made a good attempt to win mobile devs back in the Infinity Blade days, but given their recent focus (not to mention lawsuits against Apple and Google), it seems they intentionally decided to deprioritize mobile and focus on PC and console.