I have to agree. I can’t answer for everyone. I am a pretty dedicated shooter and a guy who likes, wants and is motivated to learn new equipment. I think I ran DA/SA guns for 3-4 months and 8,000ish rounds before everything was routine and I never occasionally forgot to decock. Probably the most important lesson was learning to thumb the hammer before holstering as I caught myself wanting to holster a cocked pistol more than once.
Plus the errors I made in handling toward the end of that training period typically occurred during unusual events such as after malfunction clearance.
I like to think that at this point decocking is as normal as breathing but in a totally chaotic situation (such as a legitimate shooting). I still think I could forget to decock.