Surely it’s not the agency that decided “The client won’t pay because you didn’t do anything” or whatever.
There are strong agencies and weak ones. The weak ones are what you are all calling “scam artists” when that label should be reserved for banks, and other financial sector firms.
Picture This:
Agency Rep Cold calling a haulier’s office for new business:
Rep: “Oh PLEASE let us supply you with drivers this summer!”
Clerk: “Hmmp. Will your guys let us clip them both ends every night?”
Rep: “Yes, Oh Yes. You see we said ‘9 points OK’ in our literature - so our guys are chomping at the bit for some action!”
Clerk: “Hmm. Ok then. What about hourly rates? Can you undercut the minimum pay other agencies are getting from us?”
Rep: “No problem SIR, how would you get around the minimum wage though?”
Clerk: “Easy. If the Engine ain’t running, you don’t get paid. All our vehicles have got a spy in the cab, so if anyone tries leaving the engine running at the traffic lights for example, they’ll get a bollocking!”
Rep: "Do you reckon we’re ‘game on’ then?
Clerk: “Yes, but don’t forget we’ll only be paying as much as minimum wage on a self-employed basis with you getting a side commission of £1.00”
Rep: “Oh yes, the old carrot of £1.00 an hour. I’m with you.”
Clerk: "No you’re not, I meant £1 a SHIFT commission. We pay minimum wage gross direct to the driver on a self-employed basis, less all the deductions we’ve already agreed. I reckon there’s easily as much as £350 gross up for grabs for those out there with a good northern work ethic, not afraid of 96 hour weeks, and pulling their tacho when the firm requires it!
Rep: “Oh all right then. I’ll come around tomorrow to get the paperwork signed up.”
Clerk: “Yes, you can use the Pay and Display car park. No sense giving out cards for a single day eh?”
Rep: “Hmmp!”
Clerk: “Oh, that reminds me. I’ve got to phone around the other agencies and cancel all those bods we’ve booked in @£6.50ph with them!”
At the end of this sorry tale, the apparent view is of two agencies ■■■■■■■ drivers off, and thus getting the blame for all the sins of the earth. Both agencies are not scammers, but just very weak at the negotiating table. The Client never gets to meet any driver who’s not actually signed up for all this rubbish, thus the client never gets named, let alone blamed for the sins the the earth normally associated with agencies themselves. 
On another note in defence of agencies, if they all disappeared tomorrow, then leave cover would be achieved by incumbent full-timers expected to pull together to cover the absent driver’s duties. If you’re VERY lucky, you might get to cover an absent driver on …hush now… OVERTIME! 
The bottom line that NO WAY is any firm going to take on a full time driver to cover 4-6 weeks a year, and the odd bit of sick!
Thus, NO new full-time jobs are created by agencies not existing at all. During the process of the agencies gradually diminishing away one by one, an hour of those agency driver’s time that remain is going to become damned expensive… Market forces being what they are! 
tool