Adjusting my browser window size accordingly, I search for "flowchart software". Only 2 organic results are above the fold, whereas there are 7 ads above the fold. 2/9 = 22%, so the OP really wasn't that far off the mark for many users.
The ads are just another form of search.
If the software company is large enough to afford a marketing team to fill Google up with ads then there's a good chance the software will also have big dollars spent on it.
Contrariwise, if the software you're looking for is already large and complex (driven by the nature of what it needs to do), then ads will mean nothing because they will be expected.
While on the other end of the scale with small purpose-built apps you will deliberately ignore ads since you won't want any bulky bloatware that can afford adspace.
- higher prices
- worse customer service
- fewer features
- the company eventually going under as they get priced out of the ecosystem
You won't find many subjective comparisons & reviews of players in the ads (it will all be companies selling themselves) and you probably won't typically find any free or open source software either.