I don't agree. Taking most other forms of mainstream media, they are divided into various areas which are, in most instances, identifiable, eg.
Commecial TV has to pay their bills so they break up their programmes by sponsor's messages. These are clearly identifiable from the station's content, the programmes.
In addition, they have other ways of doing this, such as the weatherforecast, they use sponsorship to fund that area with a sponsors logo appearing for a given time period.
Then you've got the programmes themselves. These are like the serps of a search engine. Many programmes are infiltrated by product placement (the next closest thing to SEO in this example). That's the grey-ish area that's not yet been picked up upon.
People watch Commecial TV for the programmes, not for the adverts (well, mostly).
The same goes for print media, it has adverts, editorial, and sponsored sections. If an advert is made to look like an editorial page, it must have ADVERTISEMENT clearly shown at the top to differentiate it from the editorial. The editorial is the responsibility of the publisher and the advert is the responsibility of the advertiser (obviously, the publisher has the final say if it carries an advert or not).
Why should SERPS be any different?
It's not expensive to take SEO route as the rewards for those using it are obvious. It's true that many don't have the budget (as opposed to it being expensive) for SEO, so yes, PPC appears to be the lower cost solution. That's good for the search engines because they are gaining revenues to help fund their service. At least we will know that clicking on a listing is helping to fund, or not, and that we can make judgements about the listing before clicking.
I'm glad the ASA has taken this stance.