"_Every person who has ever done in the past, has done it with and it had _" does not imply "_The only reason anyone could possibly ever do is with to achieve _". That's a valid reason to be cautious, but not a reason to make blanket statements about an entire category of thing.

EDIT: for Day1 DLC in particular, a totally valid and non-exploitative reason for it is "we had a release date that we absolutely had to hit (because of marketing, contracts, etc.), which necessitated calling a production halt well in-advance of the release date for QA and testing - but instead of moving on to the next project, developers worked on more stuff for the same game. If that was too complex or didn't work out, we could drop it and no-one would complain; but if we'd kept developing it in the base game, and resulted in a slipped release date, there would be hell to pay"