it has been stated that each generation of quirks in MHA gets slightly stronger than the previous generation this is further proven in the manga when some of the characters have to teach children proper manners and to calm them down and it is shown that the children quirks were incredibly strong. If this is true then eventually the powers will reach a level of world ending power. This is especially true for all for one which builds up stronger and stronger from each user. All might even said he purposely holds back his powers as he could destroy the local area just by jumping. It will only be a matter of time till the power builds up to the point where it becomes harder and harder to hold back. So it might not be in the near future it could be a 100 years or a thousand I’m sure someone who is good at maths could come up with an estimate of how long it would take but it will happen. Things will build up. 1 plus 1 is 2 but keep adding and eventually you will get to a billion. If all might could destroy the surroding area just by jumping at 100% power and was the 7th holder of the power imagine what the 14th or the 21st holder would be able to do.