Conclusion of my video that sandbox games has longest life-cycle cause players generating content by themself; in casual mainstream games only devs could do it (pretty obvious

Sandbox era has ended 15 years ago when Ultima Online become overthrown by new wave of Asheron's Call/EverQuest/WoW trio... UO decline was mainly caused by EA publisher when they made big mistakes in game development (AoS expansion) and destroyed part of UO sandbox elements there (full-loot was replaced by insurance). After that some years passed, but all next sandbox games failed to become popular - Darkfall, Mortal Online & etc. Their unluck made sandbox genre's reputation even worse - publishers/banks didn't wanted to give money for such games development, so the only way to create such games become kickstarter campaigns. And we, common players, gave sandbox genre good chance to reclaim lost leadership. Actually its a battle between us, players who support indi-devs at kickstarter and big corporations (blizzard, ncsoft, EA & etc) who put huge money to marketing to advert and to 'force' casual mainstream games...
What do you think about upcomming genres battle? Is is possible that sandbox genre would become mainstream again in a few years?