Are taxes and bans really the answer?

There seems to be an ever increasing number of countries, states, and municipalities that are choosing to ban or tax consumer, single-use grocery bags.  The manner of these laws varies from government to government, but is often associated with a ban on plastic bags and a tax on paper bags.  Are these legislations really for the good of the environment or just another way to generate cash flow?
One example is the tax that was put in place in Washington D.C. with the start of 2010.  The tax charges 5 cents for each plastic or paper bag that a shopper uses when purchasing food or alcohol.  Of the tax, 4 cents goes to the Protect the Anacostia River Cleanup Fund and 1 cent goes to the store.  There are currently some issues that are being brought up about the program.  A report from February of 2011 says that the area will lose 101 jobs and will not bring in the revenue that was expected.  In addition the Mayor, Adrian Fenty, has proposed in his 2011 budget that the funding from the tax be moved over to the public work department to pay for street sweeping.  Clearly this change is not directly related to the clean-up of the Anacostia River.
Some cities in Hawaii have taken up a ban on plastic bags as well.  There is some talk about instituting a tax in place of the ban.  But what I found most interesting is the statement by Robert Harris, Sierra Club, Hawaii Chapter where he observed that anything that is given away for free (like plastic bags) is not valued and often abused.  Senator Gabbard (D) observed that Ireland’s tax of 22 cents per bag that has been in place since 2007 has changed the public perception, creating an culture where being seen with a plastic bag is now unacceptable.
So then the question becomes, what will actually sway the public to abandon the single use bag, be it plastic or paper?  Since there are so many different cultures, I would hazard to say that to actually eliminate single use bags will take a variety of different approaches.  Regardless of how governments choose to tackle this subject, it will take a fundamental cultural change to actually make an impact into the vastness of single-use bags in use today around the world.