You have no idea...
Having been to Jordan just last November, and speaking to “refugees” there from Syria - most are perfectly content to remain - the only issue is the massively high unemployment in Jordan - and the laws that prevent them from having a job. But many just don’t care to go back.
And as others have said - historically, people have NOT flocked back to homelands after things are “straightened out.
The population of the US would be less than 100 million if that were the case.