Google rarely does anything about that kind of thing especially when it is a big company. I'm not even sure why they have rules. They don't seem to enforce them.

"This is a clear violation of the double serving rule."

In my view, things have gotten muddy over the years (but for good reason).
Many years ago, it was enforced to a degree that was way over zealous policing, lifetime bans with no chance to appeal.
Then, they added about four or five rules about pricing, ownership, support, biz model, etc., to make it clear when two different domains were considered to be double / overlapping.
Today, I don't think you can even find a policy or rule called "double serving", but G relies on more broadly defined standards, like transparency and fairness.

See "Unfair Advantage" here:
[support.google.com...]

If you do report a party for doing double serving type activity, G knows that legal arguments could entangle many parties, so they tend to not comment on cases, or follow-up.
I think this can be frustrating, but if you've ever been entangled in any legal cases, like I have, you'll come to see G's treatment as having an upside for you.

I've also been doing this long enough, that when I see true shenanigans going on, I know it won't last forever, even if not enforced (in your view).
People who resort to unfair tactics, usually aren't the competitors to be feared.
:-)

This topic can be toxic, so I rarely comment on it, people's ideas of fairness do differ.
And when one is impacted by it, it can feel very weighty.
A broad view, especially on price / service / support / availability / etc, should be taken - if the consumer reasonably feels that two choices are different, chances are very good, that G will conclude the same thing.

You know, this conglomerate of newspaper ads that are double serving (actually quadruple serving and more) are only hurting themselves. I say this because their bids from the lower ads are only driving up the click cost from the higher ads. So in the end they hurt themselves IMO. I cut back advertising 90% and now make more money than I did before. Obviously this advertiser had jacked up prices so high it was unprofitable. But very disappointed by Google on this.

This is direct from Google:

"Unfair advantage"

The following is not allowed:

Using the Google Network to gain an unfair traffic advantage over other participants in the auction

Examples: Affiliates that advertise on Google Ads against the applicable affiliate program rules, promoting the same or similar content from multiple accounts on the same or similar queries, trying to show more than one ad at a time for your business, app, or site.

Is each newspaper a different business?

Businesses use double serving tactics to block out competitors and I reckon it's prevalent across industries. I'm pretty sure you can report these instances to Google but they don't enforce aggressively.

I've dealt with these strategies before and owning organic slots can generate alot of traffic.