So it's better to pay less for an unreliable solution that sucks, than pay more for a guaranteed place at the top of the front page?
And if your content "isn't at all desirable" then how is SEO going to help? "We have stuff nobody wants, if only we could get on the front page they'd buy it!" doesn't seem like much of a business plan..
Some will say that they think people don't click on ads (which in general is false). For some terms clicks can be very expensive.
There is plenty of spammy leads campaigns that Adwords won't let you on that will absolutely make you a lot of money if you have good search position, half the stuff on http://www.clickbank.com/ Think diet pills and similar.
And if your content "isn't at all desirable" then how is SEO going to help? "We have stuff nobody wants, if only we could get on the front page they'd buy it!" doesn't seem like much of a business plan..