That's exactly how Google Flights used to work when it was linked from search results. Now users get the benefit of competition and get to choose from a variety of intermediary services.
I have a mixed feeling about this. One one hand when I search for something google directs me to content farma, not directly to place I want to visit. For example if I search for pearl I would like to see Perl site, not 'best languages of 2024'. This has not yet been do, it just illustrates my point.
Google Flights is getting to be unsafe to use due to the proliferation of fly-by-night "travel agencies" undercutting the legitimate sellers by a small amount and getting users sent to disreputable pages to collect passenger information and payment. I almost fell for one of these scams after naively assuming Google Flights _surely_ wouldn't partner with illegitimate sites for ticketing... but that's the way things are going now.
They do and always have. They also include booking services as sometimes those have better deal or maybe you have points with them or something.