My guess is that it started with the simple idea of "we want to move to digital so we can phase out retail and get more out of each sale like steam does" (pressure from shareholders and increases in development costs).
Then they probably went through every worst case scenario possible, like a group of friends sharing a single licence of skyrim and just leaving their consoles offline, and made rules around them.
It probably didn't really click with them and they thought this was a great idea up until the point they got absolutely grilled at E3.
The thing is with steam, they don't really care about people sharing steam accounts and being offline, it's only a violation of the TOS but they have no checks for it since it's not a rampant problem. I think if they sold games for a decent price and trusted their customers they wouldn't need any invasive DRM schemes.