I swear people always say nonsense like this and when I ask for specific queries they stop replying. Check my history if you doubt it.
I don't doubt you saw ads, but Google very strictly limits the percentage of the screen that can be ads or percentage of results. If you can find a single query in which every result on the first page is a sponsored ad I'll send you $5 via Venmo right now, no questions asked.
people just like saying 'omg all my screen is ads' and then they crop their screen showing like 20% of the screen on a 1080p monitor. >_>