I'm just about to attack the Cerberus base, I've got like 3300 EMS.
I didn't play multi, did all but three or four missions (which I missed because of a priority mission) basically all of the assets that could be found in systems. Got both Geth and Quarian, Truians and Kogran working together, missed out I think on a portion of the Salarian because I wouldn't sabotage the Krogan.
Honestly from where I am at it seems like you have to play multi to get to that magic number.
This issue, and yes it's an issue, can be easily fixed by either upping the value of primary and secondary assets or just changing the readiness from %50 default to maybe %75. I have gold Live and I do admit the MP is fun. However, it's just not right for some people.