I feel like your post derailed towards the end, but yeah I generally agree people don't respect Supports enough. There are even some Support mains on here that don't respect other Supports or themselves. I actually don't think that is the biggest issue though.
Yes off meta picks should be respected, but you need to have a purpose for that pick and be experienced with it. How many people understand that? From my experience as a Support main, there are few that do. The reason there are so many Janna and Thresh one trick supports is because they fit neatly into a variety of situations, and even when they do not, they have played them so often that they know how to stay on track.
Another thing is you need to get Sightstone. You just do, no matter who you are playing. I wish Riot would fix that, but right now if you don't have a Sightstone you're going to get smoked by an actual Support main.
I made it to Gold last season playing only support. My mains were Soraka, Janna, and Leona.
The issue with making supports do crazy off meta things is that we weren't meant to do that, and that actually ties into the larger issue with Supports. We're meant to help secure kills and set up plays. There's creativity and cunning that goes into that, but it isn't usually appreciated, even in higher ELO. Other roles usually can get away with off-meta builds because they only need to do one thing, and that is damage. Plus they control the income they receive through farming, and they have a lot of it.
Supports do not scale well. We cannot farm, most supports have crap wave clear. No matter how good we preform our level and builds rarely reflect that. You can be 1/0/5 and still be 3 levels behind the 0/4/0 enemy Sion with decent farm.
So if you're going super crazy off-meta, you aren't going to be getting as much reward as you would with a regular build, ESPECIALLY if you're trying to go off-meta using expensive items. Support items are usually pretty cheap for a reason, and even then we rarely reach full build, and when we do it is AFTER every other role has.
While there is little creativity in our build paths, there is in how we go about managing the game. That's what people should understand as support.
What I would like to see is Riot recognize Support contributions through the stats. Not only for teammates, but also for people looking to improve. I want to see how much damage I saved a teammate from through shields, or how much damage I've buffed through items.
Honestly though? They need to tackle the worst aspect playing a Support, and that is scaling. Nothing makes you lose morale more than being so far behind everyone else no matter what you do. I can see how that wouldn't be appealing to most people.
I would still take a meta Support over a crazy off meta pick given the choice as ADC. Why? It is not hard to play a basic functioning Support. All the ADC needs to do is get their items then siege towers. At a base level all you need to do is provide vision, and keep them in lane for as long as you can. A competent ADC can generally work off of that. It isn't anything exciting and fancy, but it gets us through the game.
The issue most people run into is that they don't often get those ADCs, and a basic functioning Support isn't enough to carry most of the time. After so many games as Support I know I can generally keep an ADC that is playing poorly afloat if they're willing to work with me. (ex. listen to my pings and focus on farm.) I've played many games where I point and the ADC deletes, and their insane scaling keeps us going.
Many people who are autofill Support can't do that though, and generally try to build straight damage. They end up failing miserably in my experience, and make a bad situation worse bot lane. Or worse, hurt their ADC's chances bot lane. I've seen so many ADCs who were playing well get derailed by a Support pick. They still have a chance, but their room for error becomes even smaller in an extremely unforgiving lane.
Another problem right now is that bot lane is incredibly deadly. Marksmen aren't weak early game anymore, and your lane can easily snowball out of control.
TL;DR
There are many things contributing to the Support role's unpopularity, and many of them were a long time coming. I know many longtime Support mains who gave up in season 6. Being a off-meta Support in ranked will only get you so far, especially if you don't understand why you're picking something, which most people don't. Picks like that can back fire as easily as they can carry, and people need to understand that.
Your pick is your choice, but if that pick doesn't work then you need to accept responsibility for your part in the loss. I've never seen an off-meta Support do that.
The Support role does need to be updated, so let's hope that Riot looks into it in 2017.
Also people claiming that Supports don't criticized for every move they make are kidding themselves. If you mess up people instantly assume you haven't been pulling your weight all game because there is nothing concrete you can point to. You're a very easy target as Support for irrational venting. Sometimes you don't even have to mess up to become a target, and it comes with the territory in a game that has increasingly become so damage focused.
I used to be a top lane main, so I remember what it was like playing other roles. Bot lane, both ADC and Support, get criticized way more for their builds because there is almost no reason to go off meta, and in some cases you end up hurting your chances doing that.
However just because there is a reason behind it, doesn't make it right.
or 
and just float/feed while waiting to forget they ever had to support, win or lose.
