China and India are densely populated countries and don't really prioritize the sport of football so if you want to host one of them as the host of the World Cup you have to prepare well in advance so that there are improvements and efforts made so that spectators and players from various countries feel comfortable when compete and lived there for some time.
I don't know whether this option is a good one or not, but I think that with more and more countries that have never hosted the World Cup becoming World Cup hosts, the love for football in these countries will also increase.
However, considering that China and India are densely populated countries and have insufficient football facilities, maybe FIFA will consider all of them if you want to choose one of them.
I would disagree if you claim that there are not enough stadiums and other facilities in India. Here we have a very popular league known as the Indian Super League, which is played in stadiums with capacity of more than 50,000. Anyway, if these stadiums are not up to the international standards, then there is always the option of upgrading them. And I am sure that the situation in China is much better than what it is in India. There is no logic in ignoring countries such as India and China for hosting rights, while awarding the same to smaller countries such as Qatar.