Underrated idea but very complex in practice. Contextual is coming back regardless as third-party cookies go away. But, I think “traditional” in this sense means brand advertising with broad reach, not micro-targeted messages for narrow audience. Like, why don’t you see nearly as many Coke ads online as you do IRL?

Hypothetically, this kind of advertiser wants “brand safe” context (high-quality, inoffensive, not-too-weird) but is otherwise mostly looking to reach as many people as possible in its core demographics. Figuring out if something is brand safe at the margin is pretty tough and you actually can’t trust ad exchanges for this signal, so that’s what at least some of that JS from advertisers is for. Also, “the margins” on the internet are huge, likely most of the page. Internet has not done well here, traditionally.

These advertisers traditionally loved primetime TV and glossy magazines, with high production values and usually safe content. A surprising amount of this brand money is still in traditional linear TV advertising, despite the fact that most key demos have already given up on linear TV.

Another problem with online ads vs traditional media is the lack of human review.

I know I can trust ads that are shown on public transport or in a major printed magazine/newspaper to not be a fly-by-night scam, malware or bullshit dropshipping operation.

On the web, I know I can not trust anything because none of it is reviewed, the ads change depending on the time of day and who looks at them (targeting) and stuff like Taboola/Outbrain are running their entire business on churning out obnoxious content.