Following the announcement I made today.
What I'm trying to say is that, the future Izuku expected us to see wasn't even that good, yes he is still a Hero, but only because of the help of his friends who funded a suit that is a replication of his own powers, meaning that he only gets to become a hero after receiving the case.
The ending shows how their story came to a conclusion, not "His" story came into conclusion. Most fans sees that Izuku could have become the Number 1 Hero, or become much more, people even expected him to died while trying to save Shigaraki but no.
What's worse is that the final battle didn't even make sense with the conclusion. Izuku was meant to save Shigaraki, but failed. Yes he won the war but he didn't win the battle, he didn't achieved anything and I personally think that's the reason for this ending. If Horikoshi went to that path then the story could have taken a better turn