Mishpacha magazine in English reviewed a report by the Taub Center in Israel which offered some suggestions.
One big reason is the "third generation effect". In 1979, 85% of Charedi men 33-54 worked. In the years that followed the percentage dropped to well under 50%. That percentage plummeted as Menachem Begin and the Likud removed the limits on army exemptions for Yeshiva students allowing the kollel only generation to really take root. The generations that grew up in the 1980's and later were raised with a torah/kollel only mentality Those who became long term Avreichim in the 1980's and 1990's had working parents to help them out and therefore were able to manage albeit living simply. However, these Avreichim are now marrying off their children and have no money to help their children at all. Therefore, the children are having a hard time making it at all even living simply as they simply don't have the money to pay a mortgage, buy food, clothing, etc. for a large family. The next generation will be even worse off as this generation at least has grandparents who worked who can help out a little, in 10-20 years even the grandparents will have been in kollel and will have no money to help out.
In other words, the Charedi community as a whole is running out of money. Generations of not working takes its toll on the resources and the hard earned money (and German war reparations) from 2-3 generations ago are basically depleted.
The report concludes, "this is something that should be worrisome, first and foremost to the charedi sector itself".