After contacting the offices of Susan Combs, the Texas Comptroller of public accounts, I was able to get some clarification on the issue. Tax is not due a second time if and only if
the buy-out cost of the leased vehicle is less than market value (rarely the case) OR if the lease agreement includes a "must purchase" clause (typically known as balloon financing). It is true however that when you first pay taxes, you are simply covering the amount owed to the lessor by the dealership if applicable. In other words, as in any other business scenario, the costs of doing business are simply being passed onto the consumer.
How would you feel if I told you there’s a strong likelihood you are being double-taxed during lease buyouts?