I have been thinking about this as well. I am sure there is some probelm with a spending side tax rather than income. Probably subversion of the tax. Undertable deals, street vendors, etc. With income they make the company track and get their cut before you are able to subvert anything.

Also our economy is very credit based with the use of credit cards. If taxes were all collected at point of sale there might be probelms with defaulting and who gets the money if people don’t pay.

I am not an economist. I am sure someone has thought of it already.