Sometimes I really wonder why people underestimate supports and don't see them equal to other roles. I occasionally play mid lane and that's the time when I clearly realize how important is the role of support. Yes, I main support, mainly "protective" supports like Soraka, Janna, Lulu, Karma, Nami, but I never thought about myself as about someone who just got carried to higher division because of that.
But seriously, some people claim that when your main supports like Janna, who can just shield ADC, stay behind are getting carried by their teammates. Is it true? Well, from my experience, no, it's not enough to just do that and get carried. I don't doubt that some people below dia (not all, but just my experiences) think about supports this way because there are not very good players (no offense). But when it comes to higher diamond/Master/Challenger you need to have a really good knowledge about a game if you want to play and main supports. It's not just about shielding on cooldown your ad carry. Claims like "supports like Janna getting carried, no real supps" are literally giving me cancer.
Role of support, the real support is about having a great map awareness and also control with a well-placed vision across the map (stealth wards, vision wards) and also clearing enemy's vision, it's crucial for winning a game (ambushes, facechecks, objectives). Also, you need to have a knowledge about what you can afford in trades on bot lane, know how to position yourself in team fights to not die and the most important thing is that you need to know how to protect your ad carry. And it most cases when you are against a team with a lot of assassins or tanks or just fed mages you have a big struggle to do it the right way. Not to mention a win on bot during the laning phase is based mostly on how support performs.
To explain furthermore, in my opinion, it's not easy protecting an ad carry even if you play "an easy" champion like Janna. Honestly, she might have fewer skillshots but the thing is not many people know how to play her in the correct way. First thing is you need to know how to trade on bot lane which is really difficult against aggressive supports like Thresh/Braum/Bard who just take ignite and after they land some skillshot you are usually dead (or your ad carry). Not to mention the importance of Janna's ultimate and Q spell. You need to have a good reaction time in team fights and use the ultimate properly, otherwise, you can fail whole team fight/your ad carry or someone else die.
Main supports, don't get annoyed by people who don't appreciate your role. There's absolutely nothing wrong with gaining supports if you really enjoy that :).
