First, the clerical and administrative requirements. It's tough enough to set up e-commerce as it is without also having to track purchases by whatever state's perverse and Byzantine tax infrastructure. My God. But let's assume the payment gateways handled this at their end. Fine.
Next: the $$$. I don't know about you, but I'm not a good enough marketer (or developer) to overcome yet another 10% vig on my productivity. I already get to keep less than 50% of what I earn. If margins are razor thin at the equilibrium price point without taxes, then the addition of taxes simply causes business to fail. Not everybody's margins are this thin, but small businesses often are. And that's who this bill would ultimately hurt.
Not to mention geolocation issues. We already can't say with any certainty where a particular IP address hails from. Oh we can get it 80% of the time. But proxies, dynamic IPs, mobile connections, cloud the issue. What happens if you're actually in California, but your cellphone is talking to a relay in Nevada, and you live in Texas, but you're buying a product from a company based in Florida, but of course the actual product's not in Florida, it's at the warehouse in Missouri. The last person in the world I trust to make sense out of this is a politician, or a politician's trained IT monkey.
Ranting aside though, I don't see any way to change this. The government will have its due, and there's a notion of "implicit collusion" among corporations: which is that incrementally and over time, competition can be squashed by raising the barriers to entry through taxation and regulation.
The Internet threw a screwdriver into the gearworks, but rest assured, they'll get you my pretty. And your little dog, too.