One thing that keeps me on Firefox, that I've never seen another browser implement, is per-tab profiles. Chrome and Safari also have profiles, but they require one profile per window.
That's the "MAC" (Multi-Account Containers) that the article was referring to.
(They're actually not full profiles, and in fact there's active work right now to make separate profiles more ergonomic in Firefox. Container tabs are way more useful for me, though.)
