Pentax seem to have been rather complacent a few times, they held back before changing to the K mount, the M42 screw mount was a constraint for faster lenses.
This is what I used to think, however Pentax at the end sold more cameras than Canon and Nikon combined, I think;
Also, in 1964 (spotmatic introduction), Pentax was perhaps the only brand that offered a lightweight, professional-quality 35mm camera with TTL metering. Fast forward to 1971 and the Electro-Spotmatic was the first camera to offer built-in auto-exposure (the Canon F-1 required a BIG accessory set to do this, and this comes from a canon fanboy like me).
So perhaps from 1972 to 1976 Pentax was perhaps "outdated" since the other manufacturers brought out bayonet-mount cameras with auto-exposure.
1976 was the introduction of the K-mount and this is seen as being "too late". However, I don't really think the M42 had any inherent problem except speed of mounting-dismounting. The K1000 wasn't any mistake, and has outsold many cameras.
Where Pentax perhaps took too much time, IMO, was in releasing the M-series cameras, which were the answers to Olympus' OM system. However, the MX is perfect and sometimes I consider trading one of my Canon F-1 or Nikon F2 for a mint MX or (better) LX. They also took IMO a bit too long in introducing a pro camera to go against the F2 or F1. The LX was too late (1980), a fully Pro Pentax should have been released in 1971... Well, the Spotmatics are almost, almost "fully Pro" cameras.
After many years of Canon fanboyism and Ca/Nikon lens collecting, i've come to appreciate Pentax and Takumars a lot. Sometimes I think that Asahi Optical is the true great Japanese camera/lens maker, not Canon nor Nippon Kogaku nor Minolta. The Takumars are always designed for
practical use, that is, giving a priority to bokeh and rendering; and the cameras are always engineered with excellent ergonomics; I would love for my Canon F-1 or Nikon F2 to have the ergonomics of the Spotmatic, MX, or even my lowly P30 (which is very nice.)
I got a SP500 recently and kinda wish I'd got one back in the 70s instead of an OM1. It feels nicer.
I agree with you. I never understood the appeal for the OM-1 and OM-2. The SP spotmatics feel better built and of course more rugged.
The Pentax MX, which I finally own, is IMO superior in
every respect to the OM-1.