Here's what you don't get. Hell, here's what NO ONE gets: Who fucking cares about defensive utility (Not literally, so don't insta-downvote me. Follow me on this.)? The real point of supports outside of all the side jobs we layer the job description with to make it sound all big and important is to be strong early so you can help your carry, who's gonna need to scale, get a good head start into scaling faster while you steadily fall off. If you do that, you did your primary job.
Now, follow me here. Remember when
utility was actually really potent early
? Yeah, that got nerfed because EVERYONE HATED IT. Because of this, supports in the traditional sense aren't as strong early anymore, so people are turning to mages with strong bases to do the support job, because the REAL support job is to be strong early to help someone, that's usually pretty weak early, get strong faster. Whether I'm doing that by making sure you don't die ever or I'm doing that by making sure the enemy doesn't live longer than 2 minutes in the lane is up to me, but if my carry scales in harder and faster than their carry, that's the main concern. If we want mages to not be played as supports, something has to be done about traditional picks so they can be stronger early without people hating their play patterns. Now, be honest, would you REALLY want traditional supports to be stronger in lane, given their usually non-interactive play styles? If so, the solution's simple.