New York bought a tunnel boring machine for roughly $8 million, used it once, and entombed it in concrete under Park Avenue. Digging it out would have cost $9 million. So they held a small ceremony, sealed the chamber, and walked away. That's the industry norm. When the Channel Tunnel was finished, machines on the British side were steered off the main line and buried under the seabed. One that made it out was auctioned on eBay for £39,999 and cut up for scrap. Boring machines get treated as…