World of Warcraft.
Even in the Vanilla, a level 60 character was like a god compared to a lvl 1 character. You could 1 shot a lvl 1 with your weakest unarmed punch or AOE tick.
The expansions made the gaps even bigger by not only increasing the lvl cap, but also adding extra gaps in the item levels per expansion. Basically, the difference in power between a capped character from the latest expansion VS a 60 level Vanilla character is probably even bigger than a Vanilla lvl 1 vs Vanilla lvl 60. So imagine a vanilla lvl 1 VS a capped late expansion character. It's like comparing an elephant to an ant.