Pretty sure, don't forget that while Acti has COD, which is massive, they don't really have much else at all. They have the occasional Blizzard release, but those are pretty irregular and only on PC. By comparison EA has regular releases of
Battlefield/Medal of Honor
FIFA (which is a juggernaut by itself)
Need for Speed
Various other EA sports titles (Tiger Woods etc).
Activision is really scraping around without COD, they have a few licensed titles like Family Guy and they used to have Star Wars but apart from that?
Well, let's take a look at the numbers, because impressions can be misleading. I agree that the EA portfolio appears to be a lot more diversified and, frankly, more interesting than the Activision portfolio. But the Blizzard factor is much more than an 'occasional' release... it's a constant, huge stream of revenue. COD is in decline, but only a very gradual declline. Most publishers would wish to have a 'disappointing' debut sales of 'only' 7.4 million, as Black Ops II just had. Although it looks like EA is starting to turn things around, they have years of losses to make up for, and they aren't publicly stating what they big money burn is... we could speculate that it might be too much spent on marketing without enough return, overpaid execs, etc., but it's not something they have any interest in discussing with the public.
The fact is that over the last four and a half years, EA has lost nearly as much money as Activision has made. EA's losses total 2.145 billion, and Activisions profits total 2.411 billion. Looking at the charts, we can surmise that both companies' accountants have different approaches to moving the numbers around within the fiscal year, with EA trying to show as much of a profit as possible in the final quarter, while Activision tries to show as little a profit as possible in the final quarter. But the overall picture is clear.
Another way of comparing the companies is to look at their market capitalization, which is how analysts estimate the overall monetary value of a company -- influenced by their recent performance, but with a longer term view based on things like the value of their IPs. EA's market cap is currently about $4.6 billion. Activision's market cap is currently almost $13 billion. For reference, Sega Sammy's market cap is just slightly less than EA's now, at about $4.5 billion.