DRM, STEAM, UBI, release date, Confused!!!

[mjfur]

I've read thread after thread after thread and all it does is confuse me.
Can someone answer some of my questions in simple terms (as if they are trying to explain it to a 5th grader)?

I have been flying IL-2 for years and have all of the CD's/DVD's associated with the game. These games are loaded on my harddrive and I do not need any type of internet connection to fly single player missions.

If CoD uses/has STEAM will the game be loaded on my hard drive or on a STEAM server somewhere?

If CoD uses/has STEAM will I need an internet connection to fly single player missions?

If STEAM goes out of business or breaks down will I still have CoD to fly?

Who, what, where is a DRM? How does this affect me?

I currently have a pre-order in with UBI (USA), should I keep it or cancel it and get the game somewhere else.

Totally confused! Please help!