Like with ANY ball on the current market they come and go, some balls get an extended stay for several years. 2 that come to mind, Brunswick Ultimate Inferno and Storm Hy-Road.

Yeah it's sad to see certain balls eventually disappear to never be seen again unless it's by video on youtube but it's the nature of the beast. I have 3 balls that I wish never went away. Storm T-Road pearl, Track Synergy, Quantum Double Helix.

Buy some while they are still available...

This. Or get lucky and have someone give you one. I had someone give me a Marvel Pearl with only 12 games on it. I'll probably get it re-drilled next season. The MP has been my workhorse the last 2 seasons. I just match up perfect to that ball.

Well hammer did re use the mask gask core in the taboo series but there covers are stronger. Kinda like the virtual gravity and the gravity shift compared to a nano or nano pearl.

I do know some balls stay longer as with the hy-road and ultimate inferno, but I just feel sometimes its better the way things are now than with a change. I feel th iq has no purpose as with a ball like the iq (pft). Maybe I just don't know because I haven't thrown it. Anyone else feel the marvel pearl should not be replaced? It's core and cover match perfectly. To me, a rolly core matches up better overall if they are paired with a weaker cover unless you are bowling on the heavy and or longer patterns. Hence, marvel pearl, iq tour series. The nano is a beast on the heavy, but not very usable on other conditions for people with higher rev rates. Push the shape lock hd to a new line storm. When is the last time you have seen a storm ball not in the premier line with an assymetric core? This and r2s would be interesting. Hmmm.......

To me personally,

The balls that often come with an assymetrical core are often a bad matchup.  There are exeptions but its still out there. By the way, I thought it cost more to make new cores. I enjoy some assymetrical balls once the track is worn or when it becomes older.

why would it cost more to use a core that's still in production?

Then how would it be impossible for storm to make an asymmetrical mid priced bowling ball?
Hey what a min.... why doesn't storm try nrg/yerg with the original shape lock? The covers back when this core was unveiled weren't nerely as strong as todays. Of course ill prob won't be happy til I have a parardigm core in my hands. Thinking about going to buy a cyclone. A 2.52 rg and diff of .052 is very close to what I want. And then a long and strong layout with a p4 weight whole could be very simil.r.

JMac makes a great point. And yes all track balls have a marked MB, however, they are not all pre-drilled asymmetric. Every ball spin up somewhat on a determinator after being drilled. The PSA will spin close to the largest amount of mass removed or the actual PSA. But pre-drilled, if it doesnt have a pre-drilled inter diff of .008,... IT AIN'T ASYMMETRIC!

Rook,
It isnt really possible, atleast not yet. Storm's never done it and I dont see them doing it when they can manipulate a large symmetric core. Listen, bowling balls arent cheap and companies arent going to mix-n-match cover/core without a purpose. Simply put, Storm looks at deficiencies in their equipment and then makes improvements.

Example, the !Q solid was new cover technology that didnt sell well. So to reuse the tech and save money, an older successful core with a higher RG was used to create more backend and, viola!, the Reign of Power is created. It has to make sense.