Originally posted by robjmitchell it would be crazy from them to tool up for a production run of Pentax mount lenses that will sit on the shelf for years
There's more to their strategy than just volume. They, for example, hardly support Sony's E-mount, despite Sony mirrorless being very popular. I don't believe they have any lenses for FF E-mount, and only 4 standard primes for APS-C E-mount. All they really support in Sony is the very low-volume A-mount, which they make about 20 lens for.
Plus Sigma usually make all of their DC and DG lenses available in the hardly bestselling Sigma mount too. In MUCH smaller production runs than any K-mount lens they might make. And much more likely to sit on the shelf for years.
So there may be some business/IP licensing/strategic? thinking behind Sigma's mount support decision-making. They don't act as if they are just producing for likely sales volume. Otherwise, all they'd make is Canon mount lenses.