It's an old thing, but rewatching this video I got reminded about Ross's DLC vs expansion pack rant. I think Ross wasn't quite characterizing the former fairly, or at least painting them with too broad a brush. When you look at DLC totally for a lot of games, it's more that the developers chose to release what would have normally been an expansion pack in an episodic format, for about the same price and length. The standard for an expansion pack in the late 90s to mid 2000s was, roughly, a single-player story-driven campaign one third to one half the size of the base one, a few new weapons/powers/units/whatever, a few new bosses, a few new enemy types, and occasionally some minor new gameplay mechanics. A lot of collective DLCs give a similar value for what an expansion pack would have retailed at, e.g.
(total cost listed in parenthesis, playtimes ascertained via howlongtobeat.com)
Bioshock Infinite: Clash in the Clouds + Burial At Sea Episodes One and Two ($40)
Dark Souls 2: Crowns of the Old Iron King, Ivory King, and Sunken King ($30)
Dark Souls 3: Ashes of Ariandel + the Ringed City ($30)
Doom Eternal: The Ancient Gods Parts One and Two ($40)
Dragon Ball Xenoverse: GT Pack One + GT Pack Two + Resurrection F Pack ($30)
Elder Scrolls Skyrim: Dragonbord + Hearthfire + Dawnguard ($45)
Fallout 3: Broken Steel + Operation Anchorage + the Pitt + Point Lookout + Mothership Zeta ($50)
Fallout 4: Far Harbor + Nuka-World ($45)
Fallout New Vegas: Dead Money + Honest Hearts + Old World Blues + Lonesome Road ($40)
Mass Effect 2: Price of Revenge + Stolen Memory + Firewalker + Overlord + Lair of the Shadow Broker + Arrival + various weapon/armor DLCs ($40)
Mass Effect 3: From Ashes + Leviathan + Citadel + Omega + various weapon DLCs ($50)
Witcher 3: Hearts of Stone + Blood and Wine ($30)
This isn't even getting into multiplayer DLC, which for the most part is free and, in concert, easily doubles or triples the content of the game in question (or its multiplayer mode). Especially for fighting games.
EDIT: I forgot to mention this, but inflation must be considered too. $40 in 2002 is equal to $51 in 2012 (to give a random example).