TL DNR: Supports should ward the most but rest of the team needs to use their trinkets and cannot whine about lack of vision [most of the time] to the support because you simply don't have enough wards. In lane phase your vision job is just your lane.
Hiya, another support main here. So I'm not sure what season you started in but for a long time now warding hasn't only been the supports job simply because the support cannot do all the warding. Back in season 3 you could carry and place 10 wards. Those were the days of warding being the supports job, you wouldn't even get full build much of the time because you needed to leave a slot open for 5 wards. However in the current season you can only have 3 wards + 1 control ward (As I'm sure you know.) 4 wards are simply not enough to provide the vision the team needs.
Now I'm not trying to say the job is divided equally. As a support you are significantly less item reliant, hence the no CS. That opens up the possibility for you to A) have an item that's primary strength is warding (and is consequently weak statwise) and B) "waste" gold on control wards. ALL other roles NEED to maximize their stats, buying a sightstone is usually not viable for them. You will have more wards, and that's as it should be.
However, to actually answer to your question, you should be warding only when you can. You mention "not applying pressure in lane." If it's still the laning phase you are not responsible for any other lanes vision. Don't go ward for mid, stick with your AD and ward for your lane. In the late game "...leaving my team when I'm the primary source of peel..." should not be happening. If your team is grouped and facing a possible 5v5 situation, you should absolutely not leaving them to ward. Ward possible flank from in the lane, you should not be roaming to dragon or baron at that time. Only ward them hen there is a break in the action and you can safely set the wards up, after which you immediately back to refresh your sightstone. You can't have vision everywhere, make sure you have vision in the important places.