Pentax, for me, is all about practicality, quality, relative 'petiteness' and a bit leftfield
Their marketing in 2011-2012 sold me a K30 and the start of huge growing ever pulsating collection of equipment fuelled by horrid LBA.
Yes I am a hiker/backpacker mountain photographer and the newly acquired HD 15mm f4 Ltd. wide angle which on a K30 is a godsend, no other camera system can do this IQ for this size, weight and price.
It is crazy to omit these tiny ultra IQ primes from the Pentax K1 full frame user. A tiny 15mm lightweight prime is much more inviting than even thnking of lugging a 1kg+ zoom up mountains all day. Smallness has many advantages and you are more likely to take the camera every time.
As mainly a prime user I get into the focal length I am using and concentrate only on focal lengths within this frame all day long. Other photographers enjoy it this way too and you can see 'one lens one day' challenges etc. A single prime can tell more of the story of a sequence of photos than say a 18-300 zoom, in my opinion it is all over the place, doesn't quite gel as well and ultimately nearly everyone is doing this on social media (or just look here).
And don't forget the bokeh and art the Ltds are great for, the HD 15mm is like a painter in the hands of a good photographer, the three dimensionality is just so good.
Those new zooms are obviously good, but too Canikon for me and everyone has these zooms in these brands... similiar/same rendering, same sharpness etc.
I have seen the Canikon people with the massive lenses in suitcases not leaving the hotel car park at Mt.Teide Tenerife while I can walk all day and get photographs they won't get as they won't carry the gear to the location.
So Pentax have done well with the compactness of the full frame K1, so they cannot deprive their loyal and new custom of what they have done in the DA Ltd range!