Re: Endless
The point is that the usual suspects don't actually have the huge numbers of staff sitting around on the off chance that they'll win the contract for which they've bid - they build teams and consortia when they know the money is secure and not before.
And as we've seen with Carillion, their role as gatekeeper to major projects means that a ruthless primary contractor can pass all the "fronting" risk down to their subcontractors (accept our crap terms for late payment or get no work) and use the up-front payments from the government to prop up the dividends and bonuses.
What you're actually buying from the mega company may be very little more than its database of desperate suppliers and some contracted project managers.