My understanding is that many businesses cannot support providing the Government with amount of cash necessary pay the tax, or the net reduction in income makes running the business not worthwhile.
Note how the letter is worded to carefully state that the family members will still have some ownership and management will be maintained. While this is certainly wise acquisition tactic, it is also very appealing to a seller who is on the margin and primarily selling to avoid the death tax.
(If you are thinking, "but the inheritor will still have to pay the tax on the cash," you are correct, but paying tax on cash still provides immediate payback with what is left over, whereas running or even just owning a business or any investment asset for 10+ years and getting zero or close to zero is not going to be desirable to a great many people.)