I think this is a complicated question. The way its phrased, it seems to imply that all game content, including DLC, is conceived & completed before the game releases. Chunks are kept aside to release later for more money. I know some games do exactly this- but the thing is, a lot of DLC isn't planned out that far before a game releases. Late DLC might not even be on the concept board when the base game launches.
The question becomes- is DLC paywalled content, or extra content? Is it the fries & soda of a value meal- something that seems essential but requires a notable cost over the 'base' sandwich? Or is it more like a sundae or cake slice- an enjoyable, experience-altering, but ultimately unnecessary addition? It's hard to say, becuase it seems to vary from game to game.
I mostly just focus on the experience I'm paying for- is the amount I'm paying for the base game, GOTY bundle, whatever, worth the content I'm getting? If I'm buying DLC for a game I already own, is said DLC worth its cost for the content? If I'm happy with what I'm paying for, I don't worry too much about the rest. (I also don't buy much DLC- I'm much more likely to buy a base release, then replace it later with a Complete Edition if I enjoyed the game.)