Shrug, lots of contractors do shady work.
He said, she said.
That isn't how this works.
A good general contractor that does good work, hits his marks on timing, and pays his bills, very quickly develops his 'crew' from good and capable subcontractors. Once he finds good guys that work well together, he just starts feeding the pig.
He won't look for bids, and he won't change anything up, because when a crew of subs know each other, and interact with each other, the jobs are basically on auto-pilot. That's where the magic is, and that's where the money is for everyone.
It's a team sport - and when he goes sideways on a job, his subs will break their asses putting it right again. And he always rewards that loyalty, one way or another.
A bad general contractor has poor subs and poor production, because he does substandard work and hires the cheapest bid he can get. He doesn't have that synchronicity between regular subs, Because he never gets to keep his subs. Either they are working too cheap to get in with him, and can't make money, or he abuses them in some way and they walk.
In such a case, the money is likely to be tight, because the jobs go long, and are full of SNAFUs. When the job goes sideways, the contractor necessarily becomes a little Napoleon, trying to beat it back into shape. That means abusing the subs. If that isn't enough (and it never is when there is no working interrelationship between the crews), the only other way to bring the job to heel is to start dicking the subs to save money.
I played this game for most of my life, helping to put beautiful luxury homes in the ground. I had my pick of the best contractors to work for, and I was seldom out of work. In fact, I was usually booking 6-8 months out on schedules.
If I found a contractor to be regularly switching out subcontractors, having trouble bringing the job home on time, or having entanglement with multiples of lawsuits, there is no way I'd do business with him. Predictably, there wouldn't be any money in it, even if I needed the work. And I could quite likely lose my ass.
@CatherineofAragon 
