Ok, let's hold on a minute.
Market cap is NOT a reflection of a company's value. It's a reflection of the speculated growth of the company, in this case.
EA has been putting out consistent good games for years. This won't change. So nobody expects EA"s stock price to jump because all EA does is put out solid games.
With Zynga, it's a little different, since they only have one good product and people are eagerly awaiting the next one. This doesn't mean that Zynga's a bigger company, more successful company, is worth more, or makes better games than EA.