Morello you asked
"Why do we continue to see non-supports roaming in bottom lane?"
Because for some reason, Supports have to have shit stats. Shit bases, Shit scaling.
They are not allowed to go into any other lane, If they somehow manage it (Lulu top, Ali jungle, Anyone can add to this list it gos on and on) They are nerfed into hell.
Support mages at this point tend to fill the role better. Because Better base stats, Better scaling, Better base damage. (And in most cases) Lower cds.
is still viable top and mid.
Please try to!

all of whom have always been mainly support champions (with the exception of Janna's brief time in mid). I think that most of the best supports to play are still "true" supports.
's HP base and growth stat).
: I'm never going to die and I'm never going to run out of mana to heal myself and my minons. Even if you're stronger than me, I still win because I can't lose. Deal with it.)
have a way to heal their allies (though I'll be honest I haven't taken a serious look at 5.5 notes so maybe there were some huge changes that didn't get tested on PBE) and their CC is much more limited. For example, if your objective was to stop someone from moving, would you pick