Those two posts are conspiracy theory, nonsense crazy talk.
Do publishers cut content to be sold later as DLC because $$$$? There may be some unscrupulous examples in the past, sure, but doubtful. Games have budgets. Only so much fits into that budget. Things get cut. Pre-orders meet or exceed expectations so a budget is created for DLC. A budget that would not have been present if pre-orders were weak. Cut items can than be implemented later in DLC thanks to the new funding.
Even day 1 DLC has a separate budget from a core game, but Firaxis isn't doing that, unless you count the exo planets, which was a freeby preorder marketing gimmick, primarily - not meant as a money-maker perse.
I can guarantee no designer, and most publishers, are not cutting features to sell later. I wish more developers followed cdprojeckt red and produced DLC's as thank you gifts, but most companies are concerned about profits, but not so much to actually actively try to cheat their audience.
If you think developers are this evil, why do you buy games and why are you here on a forum supporting games?