But regardless, that kind of number is a full time job. If you're selling over the internet and making a full time job out of it, you can handle computing sales tax for SD residents. Yes, it's burdensome. Yes, it would be good to have a simpler federal framework for this. No, it's not the end of the world.
"No tax on the internet" sort of made sense in 1997 when it was a new and exciting market and we wanted to see what would happen. Now, it's just a giant subsidy for Amazon. We can put that money to better uses.