RattFink is right. It's not that complicated to find a service that automates all of this. Just like companies outsource their payroll, they can outsource sales tax.
At its ideal best, the US is a society of ideas, and those ideas are expressed in laws. Previously, societies were based on ethnicity, race, religion or military prowess. In a society of ideas, disputes should not be decided by guns, or by priests. Who else, then? If we got rid of the lawyers we would need to replace them with something quite similar.