"There will be more and more people in the future" sounds more correct.

Hi Helen. If you want to express that the number of people will increase in the future then Grammaticaitaliana’s sentence is correct and the one that is closest to your original sentence. 'People will be more (and more) in the future.' would mean something different. It’s a somewhat unclear sentence that is open to interpretation. But one thing is certain: it does not mean that people will be more numerous in the future.

It means we will meet more intresting people in life~

This is interesting. I got my sentence too. What about "Population will increase in the future."? Or "The number of human beings will get bigger in the future."?

I don't think so. I believe you can say"The population on earth will become larger and larger in the future."