Originally posted by Uluru DA50 f/1.8 is not a lens. That is a K-mount toy lens.
And this is not a joke; when Pentax issued Q with a bunch of toy lenses, Ricoh toyed around with the idea of toy lenses for the K mount. A big, big mistake. In the world of photography only certain things pass as the lenses, but this ain't that, so let's rather forget it.
All the same, recoating and repainting of certain lenses in the lineup is not same as issuing new designs. Say, during the 2017, Pentax may come out with DA200/2.8, but which has new coatings, a DC motor and tweaked design: that is a new lens. But same motors (or lack of them — same screwdrive as before), same basic performance, optical formula unchanged, but only changed coating, which is not anything radical .. well, that is still the same lens.
Who care? We don't buy the design but the actual result. If an old design is great, then so be it. Pentax release quite a few lenses recently, some of their own design, some from tamron but that still 5 DFA in short time frame. before they release a few of interresting DA lenses: modern cheap prime with DA35 and DA50, update of DA ltd, DA20-40, DA16-85... Improved 55-300.
Myself I am into ltd, and migrated to the FAltd. You'd say they show Pentax can't marke that anymore. But my point is if Sigma, Canon or Nikon were making theses lenses today they be 1.4 or 1.2, they be optically perfect, they be huge. They'd have worse bokeh, they have different colors rendering due to modern coating. That's simply not the same product. It would not be better, just different and even more expensive...
There interresting things for everybody, the consumer that want something light/cheap and the pro that want the best. And there more to come. Like a few more perfect design for the ones that are after that.
Some think we always need something new, but that only valid if what available is no good. We have already a lot more than many with the limited serie, the cheap WR kit lenses and some decicated APSC lenses like 50-135 or 60-250...