I'm guessing it has to do with advances in illumination technology. I'm sure if you called Leupold they would be happy to give you an explanation, and perhaps even hint at what the replacement might be.
It's my understanding the VXR uses essentially VX2 glass, but with some attention to indexing/matching the lenses, as well as better coatings
When they came out, I agree they were a great value (~10yrs ago), but with all the price increases, they seemed a bit pricey to buy new.
Afew years ago I picked up a 3-9x40 VXR Patrol to get me started with dialing and mils. In low light, I thought it was a definite step above the VX3s I was using at the time. Took a lot of coyotes with that scope, but ultimately the reticle proved too think for smaller varmints at any real distance. They are all that way, something about the fibre for the fire dot.
Keep an eye on the secondary market, they can be had quite reasonably. Seems like the 2-7 is the most popular model up here in Canada