Neither dailymotion could make their app , nor vimeo , nor others .

That is why they are fail .

Youtube make millions dollars every week . Because its website is inbuilt in its app , and global people , good or bad , upload videos on it every minute .
And billions of people watch it every day .
Even without advertisements , youtube earns lots of money .

Google is not much as earning , as the loaded youtube , so it fund google as well .

By making more and more people watch different content on youtube , it had became main stream app as well .