In terms of marketshare the Unreal engine probably has less marketshare than it did 10 years ago. In the 7th gen Unreal engine 3 was everywhere, but in the 9th gen the big publishers like EA and Ubisoft moved towards relying on in-house engines instead of Unreal. Square did the reverse, moving from an in-house engine that gave it a lot of problems in the 7th gen to using Unreal for many of its biggest games now.