Exactly. Beth soft will typically sell DLCs for 10 bucks so for skyrim they sold 10 million copies at least and that was December.
So let's say five millions will buy DLCs 10 * 5,000,000. And they typically release 5 such DLCs so the number becomes rather huge. Epic WIN! They don't need to sell tiny DLCs like CA do. In the end they charge 50 bucks for all DLCs full price and see how loyal fans are... Even if only one fifth of the users buy at full price the profit wil still be epic. Bigger cake, bigger share and each time they release new game the cake gets bigger.
It is far more important to create huge loyal fan base rather than try to sell tiny piece DLCs. CA's tactics are too short sighted in my opinion. And no I wouldn't have bought skyrim if skyrim was not mod friendly. In fact I mod myself. And nexus is stronger than ever in fact Beth partnered with nexus for systematically releasing mods through steam works. It's like CA and TWC are having partnership and downloading mod is very easy since it can be managed through steam while all the support goes to TWC. TWC will have increased traffic so more income from ads. WIN/WIN if you ask me.
But that's just my opinion.