An Awkward Question About “Investment”

If, as President Obama said last night in his great speechy thingy, that “[t]wo years after the worst recession most of us have ever known, the stock market has come roaring back. Corporate profits are up. The economy is growing again,” why then does the government need to invest in things like “biomedical research, information technology, and especially clean energy technology?” Why can’t these very profitable corporations do that themselves?

Just asking.