In which case you should sell your property and make bank on what Walmart would be willing to pay for it. (If you wouldn't make bank then your taxes wouldn't be prohibitively high)
Why would Walmart make a deal when they could just wait for or lobby the county to valuate your land at some excessive value and force a sale in distress?
LVT is just bad policy that sounds ok in concept. In my city, inner city residential property is near worthless once it falls below section 8 standards. The taxes are low too as result. With a LVT scheme, someone would cook up some “true” value subjectively, which has obvious potential for abuse.
It's really the same as eminent domain. Wal-Mart wants your property for a store? They just need to offer to pay enough that the LVT is unaffordable to you. You'll have no choice but to sell, even if you don't want the money and would rather keep the property.