> How much would Google charge me to put a prominent banner next to the search box saying that Google recomends w3m for the best browsing experience on Google search?

They're under no obligation to sell their endorsement. And what difference does the specific price make for placement? Suppose it was a lot.

> Anyway, the point is that's something they can do, because they control so much of search. Bing putting up a banner that says hey, why don't you use Edge, pretty please doesn't have as much impact, because Bing has a smaller market share.

How is it different than a company that just has more money and can therefore afford to buy more advertising? It's effectively what they're doing -- they could have sold the space they're using to advertise Chrome to a third party for its market value. By using it themselves they're foregoing that revenue, essentially the Chrome division purchasing the space from the search division.