Using your numbers:
* 8 million revenue
* 1/2 to pay for materials, now down to 4 million. F' it, let's say it was more than half, now down to 3 million.
* Warehouse? That's minimal. 3 employees? I don't know, let's be generous and pay them 200,000 a year each.
This dude was pulling in close to a million (after taxes). This is using your numbers. And that seems right.
Or let's put it this way: my best friend is one of these guys that owns his own business. One of these gutters/roofing/insulation/all-types-of-stuff type of places.
He does none of the actual labor. He runs the business, follows-up on leads, does all the home shows, pays for all the advertising, etc. On one million in revenue, he sees $250K. That's not $250K in profit. There's still taxes, and some of his expenses are more than you and I (he puts more miles on his car than I ever will, he'll of course pay more for gasoline in a year, etc.). But that's the rule of thumb for these type of businesses: $1 million in revenue, $750K goes to workers, materials, advertising, etc. You see $250K.
$250K x 8 = $2 million. Like I said, on revenue of $8 million, he's seeing close to a million a year (profit, after taxes).
I'm not sure what world you are living in where $1M/year isn't "that much".