Why is Riot obsessed with nerfing vision?

Im genuinely curious why you are obsessed with nerfing wards and vision in general. When I first became a support main near the end of Season 3, the thing I liked most about the role was the ability to control the map with wards and the ability to assist my team with more than just my champion abilities. Season 4 came and I was happy to see that they were helping supports with better gold options, only to realize that wards had an arbitrary 3 ward limit plus one pink that was now visible. This was a huge nerf that I would gladly give up the new gold options in exchange for old vision system but alas its a little late for that. At least I had the ability to still affect the map when I played other roles such as ADC or Jungle buy being able to buy wards. Part of the reason I liked jungle in S4 was the ability to buy wriggles and have vision without sacrificing my build path. This went away in Season 5, now if I wanted to have any decent map control I needed to buy wards or sightstone, fair enough it sucks but it really hurts carry junglers that need to outpace the game to have any relevance. S6 came along and I could no longer buy wards. Essentially, if I wanted to have any sense of vision control on the map, I had to play a support, or play a tank/supportive jungler that could justify sightstone. Yes Trackers knife was a good alternative that I took advantage of, but most carry champs besides Lee needed the extra damage to outpace the game. You can buy pink wards, but you still have an arbitrary limit that no longer needs to exist. S7 comes along and pinks are exchanged for control, nice change that is a slight buff for vision, but again the arbitrary limit remains. S8 comes along and more importantly Trackers knife is removed along with the ability to see if my teammates have wards on their 6. Are you trying to get rid of vision? Serious question, I have to play Support to have any relevant vision control. Yes 6 exists but if you have to choose between wards, vision, vision denial. You are in an unhealthy situation where someone now has to make up for where the others lack, and not having the ability to see what those capabilites are for some ridiculous reason makes it even harder. Now I've mentioned the support role alot, and my complaint is not targeted at supports (Whom in my opinion have been significantly over-tuned for the last few years but thats not the point of this post). Its targeted at the vision system, why are you obsessed with nerfing it into the ground ?