The DLC cannot be integrated into the main game without ruining the pacing and plot points.
Ep. Gladio is ~2 hours in a closed-off area
Ep. Prompto is a potentially-many-hours separate open-world and spoils late-game plot points
Ep. Ignis is ~2 hours in a closed-off area, spoils the ending, and presents you with alternate ending options
They cannot (and should not) be integrated into the main game, as they weren't designed for it. By all means, wait for PC modders to do this and force them into the campaign, and you and everyone else who keeps calling for this will realise what an awful idea it is.
I was just asking a question buddy. :P
I platinum'd the game at launch but never bought any of the DLC or hell, played it ever since then. So I was wondering, as I saw only saw the trailers of the all the DLC pieces, if they were incorporated. I admit that using 'Cheap' gave a bad first impression though, heh.