[Kunzite]

Indeed, no new, modern, incorporating latest technology FF lenses.
I prefer to put my money in modern stuff instead of old-timers.

I always see (read) people boasting with their old Pentax limiteds, but they are old.
And nobody can convince me that old lenses, with an old design and an old AF system and an old coating are better than new designs. Technology advances at such a speed that the Pentax FF lenses will soon be reduced to collectors' items belonging in a museum.

You could buy a modern Canon 50mm f/1.4, then; or maybe the ultra-modern EF 100-400mm f/4.5-5.6L IS USM? The EF 15mm f/2.8 Fisheye, with it's modern coating (unlike Pentax' ghostless SMC) is another possibility. And let's ignore the more recent FF-compatible Pentax lenses, for no particular reason

They could "need" a new mounttTo make extra profit on customers buying new FF lenses, instead of using ancient legacy glass? (Why don't modern Pentax cameras don't come with an aperture coupling anymore?)

I doubt that; it's much harder to make a profit by starting from scratch, than relying on a small but dedicated pool of customers.

First Kitazawa said they would take the mirrorless route, because that's the future. Both for the FF and the 645DII. Then they stated that they will continue as DSLR centric.

They also said they aren't interested in FF at all. APSC will be their only large sensor. Then suddenly they're interested in FF after all.

So yes, I agree fully with you on the clarity of their intentions.

Kitazawa-san never said "they would take the mirrorless route"; even as the interviewer was pushing hard towards this direction. He never promised MILC FF and 645DII, that's something you made up.
Pentax never said "they aren't interested in FF at all", you made it up as well. Back when they were preparing the 645D, the word was that FF is not out of the question, but medium format has a higher priority.
The only lack of clarity about their intentions is in your mind.

[TomB_tx]

Optical instruments and designs don't change as quickly as IT. There is no Moore's Law for optics. Some of the sharpest lens designs are from Zeiss and Leica and may have changed little in 80 years because they don't need to.

Leica made major advances in lens designs in the late 50s-70s to combat the Japanese offerings, and when they invested in computer design capability. However, "image quality" tastes change, and today people want higher contrast and saturation. So most of the popular Leica lenses are newer designs for those characteristics.
The Leica Summicron 50 f2.0 lens of today is the same optical design introduced in 1979. I have Summicron designs from the 50s, 70s and one just a year old, and they all can produce excellent images, but vary in contrast and other characteristics. Last year they announced a new Summicron 50 f2.0 Asph design made especially for pixel-peepers and digital sensors, that has very flat field and optimum correction of all wavelengths to eliminate color fringing. However it is $7,000.
Other makes compensate fringing by firmware corrections for specific lenses, instead of trying to make a perfect lens. Leica has more expertise in optics than firmware, so they stick with their strengths. However, the days when Pentax was made by an "optical company" that primarily made lenses is long past. That makes a full line of new FF lenses problematic for them. Not sure what path they can take.

[rawr]

the days when Pentax was made by an "optical company" that primarily made lenses is long past

True. Pentax used to essentially be 'Asahi optical company that also made cameras'. But even today for Pentax (like most SLR maker's, probably) the camera body just remains an accessory for the lenses. Lenses are where the margins are. So Pentax will no doubt retain a focus on developing their lens portfolio and expertise just because lenses make good business sense. The continuing addition of lenses to their patent portfolio also confirms they are still interested in having their own designs - even for FF, apparently.