Indeed, few main business sites offer advertising on their front page, unless their business model revolves around earning from direct advertising revenues.
As for Google’s threats – Google tends to be pretty fair when it comes to penalties & filters – you have to be pretty aggressive to get hit by a penalty, and filters are like the quality control aspects.
So I would expect that Google’s war on links will seek to devalue the paid links, rather than penalise the sites.
However, something to bear in mind is that a site with lots of advertising links on it could be sending it’s linking juice to those other sites, even where Google filters & devalues that juice.
So a site with no ad links could rank better overall in Google and therefore gain more traffic, simply by the fact that it’s recommending it’s own pages and content via links, rather than third-party sites.