There's many reasons the owner(s) should get paid last. That's the moral reason. From the financial perspective, I've always viewed it as a risk/reward scenario. The people who are guaranteed paychecks aren't really taking much of a risk, except the general bet that their employer will continue to exist and need them. The owner(s), however, are taking a large risk in many different ways and if they are able to make a profit, then they should get a larger portion of it.

I've always thought of it in this investment sense with the risk to reward payoff.