There aren't all that many independent travellers in Japan, and those that are tend to head to Europe. Cairns, Hawaii and other locations within 8 hours of Japan are pretty much package tour destinations. Japanese package tours tend to be short duration: 3 to 5 nights. I think few people in Kanto will travel to Nagoya for a package departure. It's somewhat mroe accessible from Kansai. But the last leg from the shinkansen to the airport works against it mightily. Also, a shinkansen ride in both directions back to Kanto adds say 20% to the cost of the package. So the catchment area may be smaller than Nagoya would like to suggest it is.
Package tours are put together by the major travel agents, for example H.I.S. &JTB Corp. Hearsay suggests J* doesn't have much quality contact with the likes of H.I.S. and JTB Corp (the biggy, turnover USD 15 billion).