That's the common thinking that if you don't have latest Android it's a problem. But some manufacturers like Samsung push security updates monthly even for old devices such as Note 4. They do have many features years before the stock Android gets them (e.g. aptX, multiwindow or even Android O "tooltips" were in Note 4 when it was announced). So what exactly is the benefit of having everyone use the same exact, latest version? I most certainly would not switch to stock if that meant degarding my "experience" w.r.t. other features.
"Be together. Not the same."