Every Offtank falls off lategame. Carrys are what matters lategame. Protect your carry and you win.
I would say, as a good jungler you can greatly carry, when your lanes skills are close the enemy lane skills. The jungler is most of the time really just the icing on the cake.
Imo you can carry yourself up the best when you have a premade playing support and play carry yourself. Because as a good carry with a support,
that protects the carry well, you can just destroy most uncoordinated teams in Low Elo single handedly.