Earlier quoted context omitted.
Mail-order catalog businesses, which have existed for decades? You only pay tax in jurisdictions in which you're physically based (for an internet startup, this would be wherever you're incorporated). This axiom has held in US tax policy for about as long as there has been US tax policy. Kinda ties in with that whole 'no taxation without representation' thing. Edit: for clarity .
Sales tax is applied to the buyer, not the seller
The problem with the proposed legislation is that counties, cities, and towns can each set their own tax rates. So the compliance costs are high because of the thousands of different rates. You cannot use something simple like state or zip code to determine tax rate; you have to use geolocation to get the exact jurisdiction. And governments typically levy penalties if you get your sales tax collection wrong. So who is responsible for paying the penalties if the third party tax collection service makes a mistake?
The way this was supposed to go down is that states were supposed to simplify the number of different tax rates before requiring out-of-state businesses to collect their sales taxes. You shouldn't need to subscribe to a sales tax compliance service to do business in the United States.