The easy answer is he doesn't have to-he's made many millions of dollars the last two years without working. Of course it would be nice if he released more tax returns beyond these last 2 years.. He wrongly tried to justify this by saying, "Gee, Democrat John Kerry didn't release them for more than 2 years in 2004."
It's often said that even in lies there's a measure of truth. Generally, that's, well, true. However, not in this case. Who knows the basis for that whopper. Actually, Kerry released 20 years of taxes. Even Republicans don't get Romney's inability to release his taxes:
"John McLaughlin, a longtime GOP pollster, lamented some of the self-inflicted wounds from the primary – “He’s been running for president for five years and he hasn’t released his taxes?” – and said Romney had to craft a concise message."
Read more: http://www.politico.com/news/stories/0412/75387_Page2.html#ixzz1sZpGT1G4
Yes, he has been running for five years which is why it's surprising he's still so bad at it. Romney just can't get anything right. He has some very poor instincts for the optics of things.
Yesterday he spoke at an empty factory with a sign that read "Obama isn't working." Yet in many ways these were poor optics for Romney. I mean isn't his image as a corporate raider back at Bain Capital someone who made money buy firing workers and shutting down operations? Isn't in reality he and his party more associated with closed factories than Obama who has shown us consistent job growth for the last three years?
The fact that Mitt isn't liked, that the more Americans hear about him the less they like him is very problematic. I know you can argue that it's not about likability it's about issues. But when was the last candidate with likability issues that won the presidency? I can;t think of any. Dukakis lost, Dole lost, Gore lost. I don't see how Romney can get over the fact that only 29% of Americans find him likable. You can argue that the more likable candidate-in the mind of voters always wins.