Good. Even the playing field. Tax everyone equally.
That is what they are already doing. If you do business in a state, you collect sales tax. If you send an item from your state to someone in another state you don’t have a relationship with the latter state so collecting sales tax on their behalf would be kinda dumb.
... If you send an item from your state to someone in another state you don’t have a relationship with the latter state so collecting sales tax on their behalf would be kinda dumb... But you do have a relationship with that state -- you have a customer who lives there.
And, the tax is on the customer, not on the business.