Sad thing is, we do not actually need to be a world that is so stuck to certain areas.
If you look at each nation, and I mean like literally all of them, you could realize that most populated areas are populated because of bad planning.
That's the mistake by government, not anyone else.
Think as a person who live in rural area, you will love to move to urban area, either to satisfy your desire or seeking better job.
Think as an investor/businessman, you won't invest your money in rural area because it's lack of customers, rural area only good for certain businesses.
Yup, the governments should make arrangements so that the people living in rural areas shouldn't be moving to the urban area, but all the facilities are there for the common man, and he should get all the qualities of life in rural areas too.
Also, both rural and urban areas have their own importance and it will not be good if everyone is willing to relocate from rural to urban areas. Also, Urban areas have other challenges that no one is talking about, like an overcrowding population, pressure on infrastructure of basic necessities like water or electricity, and most importantly, a higher cost of living.