I was wondering why it is so rare to see such caps with translucent lettering. I know Corsair now has their DCS profile PBT aftermarket cap sets that have translucent doubleshots. I wonder if they know something that the others don't, or are just taking the risk that people won't care in the long term if they shrink?
There are a few companies now that are making double shot PBT caps, some with translucent (POM?) legends. Some companies have chosen to take the risk of retooling their production lines to account for the different shrinkage rate of PBT versus ABS, and are now seeing benefit from it. Other companies may already have a full production schedule with the tooling they have, and thus cannot commit to making big changes that might disrupt production or which may see minimal return in relation to capital expenditures investments. For example, SP's SA production line is queued through the end of 2018 at least, and any new designs will probably not be in production for a year or more. They also have a large industrial customer base, although as you can see their attention has been drawn to the enthusiast community in recent years by increased demand for custom keysets.
Backlit keyboards honestly only became a thing within the last few years, so production of compatible keycaps will naturally lag behind a bit. Add to that the fact that most people don't know or care what material their keycaps are made from, or that there even exists a difference in durability, quality, and feel. The enthusiast community is growing, but we are still a drop in the bucket compared to the overall market. Luckily, some of our requests have spilled over into the "gaming" market, so companies like Corsair, Cooler Master, and Logitech have started to fill that niche to meet demand.
