Just a thought on economies of scale: 

I've been doing a few letterbox drops for clients lately.  And I've had a few calls from people who came to the site looking for a distributor.  Unfortunately they had campaigns in mind that were a bit out of my league!

But I've heard a repeated observation from these people:  They said that they get better results from the small, independent distribution services than from the big companies.

I think the reason is twofold:  The smaller operators have less businesses that they work for simultaneously, so each flyer is more likely to get seen.  Also, they're not employing so many people who may not be reliable.  (It's very easy to just dump a whole pile of flyers and then claim to your boss that you've actually distributed them!)

This illustrates a challenge many newbie business people face.  You may be able to offer a good service individually.  But your income potential is limited by the fact that one person can only do so much without collapsing from exhaustion. 

If you then grow your business, the overheads come in.  And you have to employ people, some of whom may not be up to scratch.

I can see why a lot of people baulk at the challenge.