Let's get educated. Crytek, YOU NEED TO READ THIS

Game company A released a game for 50$ USD.
Company B did the same.

Both games are equally good, some issues, but good.
But also both games have a rapidly dwindling fan-base.
The devs only option is to reel people in with Downloadable Content

Player of company A's game is offered a DLC pack for 10$ USD.
Company B offers a dlc pack too, but it's free.

Player of A tells some friends about the game's features and what can be done with it.
They ask "what's in the DLC and how much is it?"
3 maps and a few weapons, ten dollars.
50$ game + 10$ DLC = A good deal to very few. Not many will get this game.

Player of dev B's game does the same.
50$ game + free DLC = Phenomenal deal / new players / word of mouth spreads and popularity catches fire.

My point: you may lose some of the money for making and releasing a dlc for free, but the mass sales of 50$ and below used games with seriously outweigh the downside of losing that extra development money. In fact, that money lost would be massively outweighed by the tidal wave of sales coming from new games.

Think about that Crytek.

Eh. Your scenarios aren't that great, and shows a bit of stretchy logic and assumptions.

A) DLC is just additional content, and not a total and complete change of the game design; meaning, only people interested in the mechanics as is would be interested in mechanics + stuff
B) Mr. Opportunist says, why buy at $50+ free dlc when I can buy at $30 + free dlc a few months later, or wait until the GOTY edition?
C) Odds are, even with free dlc, word of mouth would still be akin to 'ho-hum average game with below average population. Pass.' Sorry, DLC (free or not) doesn't cure a game cancer.

Crysis 3 may have even sold so poorly that additional DLC beyond what was worked on prior to launch may not be released, and just cut. No sense in trying to revive an already dead cow.