First, it's against WTO rules to levy a particular "tax" at the border vs. a particular country. It's not feasible to do so as a result, as much noise as is being made, there would be huge repercussions. So the political goal of punishing an ally and major trading partner (which makes no sense anyway) isn't achievable.
So it is a tax on all imports or a tax on none.
That is reason number one why this is dead in the water.
Reason number two is that it would be extremely expensive to administer and especially if you were going to single out corporations it would make all kinds of loopholes and legal challenges. It would take years to set up and then it would be fought tooth and nail by corporate lobbyists and all government types would drag their feet and run out the clock. Depending on who you ask, they only have to run the clock out 30 days, 180 days, a year or two but four at tops. That is easy. Especially when it looks like some people may be headed to jail, Washington will be non-commital and see where the wind is blowing before setting any permanent sails.
Corporations are exempt from VAT type taxes, otherwise when you're buying and selling your parts and assembling products, if you keep paying tax each time someone touches and resells a combined widget the percentage of the value that is tax increases. Eventually the consumer pays an incredibly inflated rate that is almost all tax. This makes domestic industry not very competitive vs. imports and then you need to have huge duties, and the person who ends up suffering most is the low income consumer. So corps get VAT refunded and pay a net out of what they collect from consumers and what they have paid out on expenses.
A VAT doesn't satisfy the political desire to punish Mexico though at all so that won't happen either.
Basically there is a lot of simplistic thinking that a trade deal in which money flows more in one direction and goods in the other is somehow bad. It's like being angry that you can buy your groceries at 20% off. People could just volunteer up that extra 20% if they felt really bad about it but they don't do it. There is benefit that flows both ways here. A lot of people understand this and they will just let the anger dissipate and once this wave of populism is over, they will go back to free trade. The wall will end up in the same situation.
Bureaucrats are really good at waiting.