We run into the same thing all the time and it not just from unlicensed contactors. It is contractors that carryon insurance have no employees just use subs and have no trucks.
They reap all of the rewards of the jobs with little or no cash out lay and put the primary burden of running their business on their subs. The subs have to own and maintain their trucks, insurance if any, tools and all miscellaneous cost for little of the profit. This not just small start-up companies two of the larger companies in Houston one primarily commercial and the other primarily residential do this very thing.
One company some little start up is doing door hangers that make ridiculous claims. Tells people he will do an air-balance ($250.00 value) for free. The vast majority of the homes in this area can't be balanced because they don't have any dampers in the ductwork.
It makes it very hard on companies that make an investment in the community by trying to provide good jobs in our field with benefits and good pay. Our installers are paid hourly have insurance 401K retirement plans, vans in good condition and we care about their welfare and families. The same is true of our techs office staff and warehouse people.
It's companies like the ones you are talking about and I talked about that make it hard to do high quality work be honest and provide quality jobs for our trade.