Yes, homelessness is an industry, that is for those who offer services to homeless people - this includes everything from year round shelters to mom and pop groups that deliver food to the homeless on the streets. Scouring the internet, I could not find a total count of all the official not-for-profit organizations nor for the unofficial, yet altruistic, service providers dealing with the homeless. Certainly their numbers must be in the thousands, if not tens of thousands. There are 289 cities in the U.S. with a population of 100,000 or more. There are more than 3000 counties in the country as well. And I'd guess that homeless people live in every single one of them.
Still, from what I've seen, nearly all who work with homeless don't really understand what causes or cures homelessness. They may work hard to provide shelter and food and clothing, but they don't make much of an effort to understand the "who what when where and why" of homelessness. It could be because they are so focused on doing the work of caring for the homeless that they have no time or energy, or interest, in discovering more about the issue.
Still, these workers in the homeless industry are considered experts in the field. The general public have a lot of questions about homelessness, so they seek out service providers, hoping to get real answers to their real questions. But, these homeless industry people, lacking true comprehension of homeless issues, make up most of their answers, backed up by nothing more than anecdotal stories. Over the many years, these answers have become solidified in the consciousness of the homelessness industry, and a "canon" of knowledge has developed, as well as a philosophy of sorts about the work of homeless services.
The bigger problem is that no one has ever questioned the answers coming from the homelessness industry.
But, we are now finding out that their answers to the important questions have never been truly analysed and checked for accuracy - they have never been qualified. Most everyone has just assumed that these supposed experts know what they are talking about.
Now, science is getting involved and turning its critical eye on the entire homelessness industry, and it is changing everything we thought we ever knew about homelessness. Much of this new focus on homelessness came by way of President W. Bush's declaration that we, as a country, should be able to end chronic homelessness in a short amount of time. That is when the department of Housing and Urban Development got involved, and they in turn employed the scientific community, and they are helping the government to better understand and develop better cures for homelessness. It is because of the efforts of our government, HUD and social scientists that we have these new models, such as "Housing First" and "Rapid Rehousing". This is also the reason why the government and other funding sources are now changing how they distribute funding to the homelessness industry. Soon the government will stop funding the many shelters and other homeless services that have little or no real impact on the goal of ending homelessness. People are demanding that homeless services give up the band aid approach, (which seems to only enable homelessness) and to instead work towards ending homelessness. Homeless shelters must now work towards putting themselves out of business. And that may very well be the rub.
The homelessness industry has been doing things the same way for so long, they cannot fathom another way of doing business - their entire mental concept, their organizational charters, their philosophies are tightly wrapped around the old way of doing things. So, these new ideas that are come along, they don't comprehend them. The old school homeless service providers believe, and declare, that any other way of approaching homelessness will no work. Or, they declare that there is nothing wrong with their particular approach. Some of this resistance could be motivated by a sense of self preservation. The new way of dealing with homelessness will make many services, and their many employees, obsolete. Workers in the industry will have to relearn everything they've ever done, and that may require more effort than they are willing to dedicate to the cause.
A good example of this resistance is found in a recent article by KPBS in San Diego about the coming changes in how homeless service providers do their work. http://www.kpbs.org/news/2014/mar/26/debate-over-housing-first-may-cost-local-homeless-/
Regardless, the change is coming. Homelessness will end. Rescue missions and the like will soon be a thing of the past. But until then, people will still be suffering needlessly on the streets.