Quite frankly, it's hard to imagine a world where any hero is going to be able to bring down Shigaraki at this point. With the Paranormal Liberation Front at its absolute strongest, it's entirely possible that the power structure of the world within My Hero Academia will shift as a result. Throughout the entirety of the franchise, the villains have been working toward a "world where they will be free", which sounds all right on paper, but it means a world wherein they will be able to kill, steal, and maim with impunity! A world where the villains rule would certainly be a huge game-changers for the series and it seems like this latest story arc is going to be the start of it!
The time has come to pass the torch. With Shigaraki becoming the inheritor of All For One and Midoriya speeding past All Might in power following his retirement, it seems as if the next generation is going to step up to the plate. All Might's death has been something that has been hinted at for some time throughout most of My Hero Academia, and with this latest story arc being one of the largest that has ever taken place in the franchise so far, this definitely seems like the time that the old heroes and villains of the world will be swept away.