I play mostly support these days and I've been rising steadily through upper silver.
Honestly, support is very much underrated. Not only do you have the opportunity to force-feed your adc and cripple the enemy adc in the process, you also give your team map awareness and objective control. Also, who says only mid can roam to other lanes? Supports can gank mid too... just have to be careful about picking the right time.
Of course winning your lane isn't 100% guarantee for a win. But it does raise your chances significantly. And that's all it takes to rise in rank, given time.