Search ads isn't the only way to reach people and it's not an impediment for new entrants as shown by Amazon's ad business.

As for the general matter, google has the right to publish and design their website however they see fit, it's a no brainer, the only reason this question keeps popping up is that google has very powerful enemies in basically all news and publishing companies (they blame it for their dwindling ad revenue), not to mention the oracles and yelps of the world and all of them are piggybacking on the infrastructure laid down by microsoft at the time.