Because people don’t actually shoot. Those that do, almost never shoot off a range- even the competitions that people do are relatively sterile. Those that do shoot almost never have comparative experience between platform. Seeing 5-20 different platforms used side by side and subjected to real “weather” and conditions, with enough rounds to gather something approaching “data” is not a thing. When this people who do shoot, shoot, cleaning between days is not only ok, it’s expected. Malfunctions happen, but intentional blindness means people don’t notice. Humans don’t reflect by and large. Everyone says “customs” are better, so customs must be better- so they ignore or choose to not see the issues.
People will say with one breath that it’s all BS and that they have never had issues, and then in the very next day they they have had multiple triggers go down- but it’s ok because they just needed cleaned. People say “I use my gear really, really hard”, and then in the next breath say “rifle for sale, LNIB”, or “I would never let snow get on my rifle”. Etc, etc.
There are somewhere around 200 people that have been through a S2H class now. Around 30-40% of rifles that they have been used for the first day have been R700 customs (and a couple factory). Not one from a student that I can recall has made it through the very first day without malfunctions- despite multiple going out of their way to say we were FOS and theirs has never had a problem. Only mine has made it through pretest without malfunctions, and they have had problems roughly 50% of the classes.
Basically... humans are full of shit.
Round bottom action easy for a gunsmith to work on, with a relatively fast lock time.