When I'm in that situation where the rest of the team is struggling, I continue to pressure bot to second turret with good warding and often let the support go help the jg gank mid and top to bring it around. This gives you better map control for dragon also.
If the enemy team doesn't react to pressure against bot lane, they lose turret, if they do react it takes pressure off of mid and top.
Essentially if you're a good adc and can play smart, when you're losing a 5v5 even match, you turn it into 4v2 and 4v3 everywhere else on the map, all the while jacking up your cs so when it does come time to group and get drag you're ahead.
Once you have enough items and are feeling confident with your power, you can start taking control of objectives like drag and towers.
If you run around right away after getting bot turret, you'll waste farming time and not be strong enough to make an impact vs enemy lanes that are winning vs your team, you'll just set yourself and everyone else back by giving up cs and splitting experience, ending in a gg before 20 minutes hits.