I've been skimming LensRental and related websites and I see most all modern lens are extremely complicated, intricate, expensive but they work, mostly. I see that with a7rII, there is an insane amount of parts in it just to make it work and take shots.
However for my old Spiratone 400mm f6.3 lens, it's easy to unscrew and view the parts directly for cleaning/modification.
Camera/lens manufacturers have a lot on their plate to make photographers happy, and some of us have jobs. I can't see user-repairability being high on their priority list when designing the final product. Was repairability ever a high priority (even back in the day when lenses and cameras were much simpler) or is the manufacturers' apathy a consequence of this simplicity.