This could be explained by the 250-300 M you refer to not matching the same distribution due to

1. this seems to be google ad network specific, not google services per-see

2. the analysis seem to only include users which do in general generate ad revenue, e.g. all AD Block everywhere users are not included in the distribution

3. given the lower bound I assume ad views which have no clear attributable user, and/or users with a very low and irregular amount of views, are not included (e.g. some mostly "offline" people, people mostly using an ad-block but sometimes somewhere still seeing an add, also it's G-Ads, so anyone using only FB, TickTock etc. would not show up I think)

There are some people who don’t use Google. I use Duck Duck Go for search. Additionally, with the rise of LLMs I have been using search much less in general.

not back of the napkin - but back of the head quick calculations - number seem about right.

remember the average 'world' user is about 100x to 500x less valuable than a US user.

google's the middleman, and it won't capture the whole 1600 right?

Presumably this only counts internet users who use Google.

Caveat I'm no expert on Google ads. Never bought one, never plan to, never advertised anything at all on any service. But since I'm capable of doing a basic web search, I found:

https://support.google.com/google-ads/answer/6366577?hl=en

This is the process for determining which ads get run. The bid is only one of many factors, so as their support document indicates, the price you pay is often quite lower than the bid, which reflects a ceiling rather than a real sale price.

https://support.google.com/google-ads/answer/2580383?sjid=17...

This is their guidance on demographic targeting. Note there is no category allowing you intentionally target children. This doesn't mean advertisers can't figure out some way to do it anyway, but it means Proton can only sample from adults. Presumably, some probably very large number of the people who "use Google services" in your estimate are children, which childstats.gov indicates represent about 22% of all Americans. That makes it more like 195-235M adult users of Google services.

https://support.google.com/google-ads/answer/2464960

As indicated here, you don't pay to place an ad. You pay for clicks, so regardless of what you bid and who you target, Google isn't getting revenue for the number of placements you bid on, which is what Proton is sampling here. Presumably of the 250 x 0.78 to 300 x 0.78 million adult users advertisers are placing those $1605 average bids on, quite a bit fewer than 100% actually click on at least one ad.

revenue vs profit?

ok, and?

proton did 54,000 samples of US users and made an average of what advertisers are willing to pay to target, not what they actually did across the whole population

and plus this isn’t to inform you, it’s to sell you on another proton honeypot