^Indeed. The reissue of "The Aztecs" is far more likely to benefit from having "Air Lock" on it. Plus, in terms of budgeting restoration and/or extras for "Air Lock," it probably helps to have it on a re-release rather than a previously unreleased story, especially one with a likely animation.
Gallifrey Base, of course, was seething with resentment at the announcement that they might have to buy a story they already owned to get "Air Lock." Between that and the announcement that nothing new was being done with "Shada," the tension was... well, entertaining, actually.