Why do they take so long to free up some money so the job can get started?
It's pretty much a given that the bigger the organization, the more hoops you have to jump through to work with them. If you really want to have fun, try a couple of government contracts.
There's definitely good money to be made there, but in my experience you have to be able to wait for it. If you don't have the cash reserves to tide you over (and most small/startup guys don't), it can be a pretty tough road to travel.
But as a sub, your GC should insulate you from that. I think what you're really grumping about is that you have a bid in, but have to wait longer than you'd like to find out if you're going to be working in a week or three, right? BTDT.
Tough as it is, you just have to put that one on the "maybe" list and keep on scratching up other work until you get a go/no go. And if you get a "go" while in the middle of another project, that's a whole other balancing act you're going to have to deal with.
You could always go to work at a factory... <thump, zzz, whoosh, thump, zzz, whoosh...).