These attack will only grow in the future with the environment we live in growing more and more towards a technologically advanced system. With more technology comes more hackers, and in turn there will need to be more legislation and preparation in terms of security and punishment of the crimes.
Yes, the effects of computer hacking on the American economy as significant enough to warrant stronger legislation, because when there is a hack, it is often on a large scale. When Target's credit card information was hacked, millions of people were affected. When a crime has millions of victims, there should be strong laws.
A computer attack against the US has the potential to cripple more than just the economy. Military equipment, private enterprise, and all sorts of other areas are all tied together with the internet and computer connections. Catastrophic consequences along the lines of a hijacked nuclear weapon or the sudden input of false trigger warnings or stock market manipulation could cause severe damage and warrants increased attention.
What more do you want the United States to do here? We make most forms of hacking illegal. We find the hackers when we can, and we prosecute them. If they're found guilty, we give them harsh sentences. There is literally nothing left for our law enforcement system to do here.
I do not believe the effects of computer hacking on the American economy are significant enough to warrant stronger legislation. As we saw with Target, hacking can harm the economy in a way because the company did experience a shrinkage as far a market value. However, I believe that is the price companies pay when they leave information open to hackers.