You have to be joking right? You'd have to be blind to not see the rapid decline in Firefox marketshare.
https://en.m.wikipedia.org/wiki/Usage_share_of_web_browsers#...
https://en.m.wikipedia.org/wiki/Usage_share_of_web_browsers#...
Second, your concept of rapid decline clearly differs from mine. That is an eleven year decline and I don't think it's "rapid" at all for a browser.