Second let me acknowledge that on the merits of this case divorced from the issues we're discussing here, I agree, Columbia shouldn't be the beneficiary of eminent domain.
But your logic doesn't hold. Just because there is a fair market value for an asset doesn't mean one party will be reasonable about selling it. It's not even likely that they'll be reasonable. The unreasonableness of a seller can indeed inflict economic harm on the overall market and on the public good. We recognize this, which is why we can build interstate highways without being held hostage by 2-bit real estate wildcatters.
A friend of mine is dealing with this right now in the real estate market; she owns several properties but rents her own property. Her landlord is being foreclosed on. She's made an offer above fair-market value for the house in a fashion that spares the owner from the (dreadful) cost of real estate agency. But the seller won't budge, believing that any offer from my friend must be the market floor value, else it wouldn't have been offered. And so my friend may have to move and the seller will end up receiving less money as a result.
This kind of micro-tragedy happens every other minute in a free market and I generally agree that we should suck it up and be happy for all the benefits the free market offers in return, but it's not fair to pretend there's no trade-off.
And, come on, it's totally unfair to compare a real estate transaction to the valuation of a small business.
Also, how does your friend's example make any sense? If the seller doesn't want to sell at a particular price, it's seller's choice.
Let me take another example. I bought my first car (a used 2001 Altima) in 2004 from some guy. As it was my first car, it has a special emotional value to me. In 2010, the value of the car is around 2000$ [I don't even drive it anymore]. Let's say tomorrow Nissan finds out that it's their 1 millionth car sold and they want it back to put it in Nissan Museum. They offer me the 2000$, the market value of the car. I refuse because the car more than 2000$ to me. They offer me 10,000$ and I still refuse. What if there is no price at which I am willing to sell the car? Should US Government deposit 2000$ in my bank account and give the car to Nissan by force?
[On a side note, I believe that their is price for everything. But seller should be able to decide the price, not buyer.]
Looking at the actual case: There were two businesses involved. Tuck It Away and a gas station owned by Gurnam Singh and Parminder Kaur. From their names, I can tell you that they are from state of 'Punjab'. Most likely they are immigrants to America and they would have worked hard to set up their gas station. Don't you think it's morally wrong to seize their business property just because another private organization can benefit? What if US Government forced you to hand over your company (which you built it from blood and sweat) to McAfee for 3x multiple of your revenue? Would that be okie to you?
Please do not get distracted by 'small business' example of Patrick. We are talking about 'private property' (either small business, real estate, car or what have you) and using (or rather abusing) eminent domain to seize that private property and giving it to another private organization.
"A house kinda like your house just sold for $500k, so here is $500k, now give me your keys" is just as unfair as "A business kinda like your business just sold for $50k, so here is $50k, now give me your passwords."