I was in Google Ads from 2008-2010. At that time, there was a limit of 3 top ads and 8 right-hand-side ads. The top ads generated the vast bulk of the revenue. They were also in blue or yellow (I forget which, but one was WAY more lucrative than the other!) so it was very easy for the user to distinguish an ad from a search result. I just did the canonical $$$ search "flowers" on my Macbook. The entire first page was…
TLDR: 2 ads, the rest organic.
Top-2 were ads, a maps widget, organic result, people also ask, 4 organic results, people also search for, images, 4 organic, 1 ad.