But they like to act like they aren’t at the terminal stage of development, and it causes confusion and customer upset and layoffs.
Ads are Google's oil.
Oil happens to be under UAEs ground, whereas Google has to work and compete for its ads business (vs Facebook, Amazon, others.)
Also, UAE and Venezuela both have oil but one is doing much better than the other. How you exploit your assets (oil or historical position in the ads business) matters a lot.
Then there is the fact that their oil company PdVSA has been under US sanctions which can't help much[3].
[1] https://www.gem.wiki/Venezuela_Tar_Sands
[2] https://knoema.com/infographics/vyronoe/cost-of-oil-producti...
The 2nd paragraph shows why your analogy between ad revenue and oil revenue is flawed.
The third paragraph shows that even sticking with the flawed analogy, how you exploit the asset matters.
I can't find any source that claims this, and a few sources I could find say that it's a loss leader or that it's "roughly break-even".
Everything else is subjective and generally leads to decay.
And there are plenty of objective measures: gross margin, EBITDA, ROA, ROE, lots more. And those are just financial measures! Installed base, CLV, NPS, there are many many objective measures.