The browser is not the only place that can cache HTTP responses - proxy caches from the client's ISP and/or local WAN or corporate intranets should also obey caching rules in the HTTP response headers.

HTTP caching works. The problem with the bike share site in my opinion is instead of using established methods for scaling (like HTTP caching) and other good practices they reinvented the wheel as a Rube Goldberg monstrosity which, big surprise, didn't work.

Remember kids - don't scale until you need to.