Now if they would just come out with a nice straight 6x, perhaps with a copy of Leupold's LRD reticle
Yeah. Leupold was selling so many of those that they ran out of places to stash the money, so they had to discontinue them……
The market for a 6x42 is indeed a niche market, but it is a niche market from which Leupold walked away. Decades ago, when they were very popular, you could get then in a choice of matte or gloss to match your rifle. Customers could select a very nice duplex or a heavy duplex. Their custom shop could provide other reticles, including a very nice post and duplex, which was very similar to the Tract T-Plex. At its demise, you could get any kind you wanted as long as it was matte finish with a wide duplex reticle. The basic mechanical set up that focused by turning the entire eyepiece had not changed since it first entered production.
There does not appear to be a case for return on investment for development and production of another 6x42, particularly when you can get a better return on investment by catering to the precision rifle shooting and long range hunting markets these days.
