1. The search results are only changing for non-mobile friendly devices IF the search originates from a mobile device, not for everyone.
2. This has very little to do with ad revenue. Google is always tweaking the algorithms that feed the results page. This does not give any new precedence to paid advertisers at all.
Basically they want you to bring your site into the 21st century. I see no real issue here. Responsive sites that are designed well (IE, not slashdot mobile), can be useful, and you can always request the full desktop site (if the site honors that request). Content and formatting do not exist independently of each other. Do you want some gopher sites in your search results?