Do you really think the two expansions were pointless? At the very least, Entrenchment wasn't pointless and added a lot to the game. The single player types might argue that Diplomacy was worthwhile.
I seem to remember a statement around the launch of Sins was that frequent patching would bring in features as well as bug fixes - this was quietly dumped in favor of "microexpansions" right alongside the discontinuation of stand-alone patches and Impulse triumphantly launching like this:
Entrenchment wasn't trivial, but "a unit, a unit to counter it, and then a defense structure" is $3.99 DLC for most other games, and Diplomacy as an expansion was kind of ridiculous given how awful of a diplomatic system was in place in base Sins (and how limited and weird it ended up being).