States are actively engaging their legislature following the decision by Wayfair vs. South Dakota. I have attached 2 pictures showing the states that have changed their sales tax rules and a screenshot from the Connecticut DOR that explains the change as a marketplace fairness.
Here's an example, if a vendor sells pens at $1 per pack and sells 200 packs, that vendor will have met the economic threshold for collection and remittance of sales tax. Why? Because many states have a 200 minimum transaction to trigger remittance.
There are 3 ways to deal with sales tax (1) Hide and hope it goes away (2) "reactionary" Deal with it if you get audited and (3) Be proactive and get ahead of the curve. I recommend item 3 as the best approach.
I also recommend that if you are a larger company that does business across many states that you engage a sales tax professional or purchase software that specializes in sales tax calculation of your products.