I sheared 2 in the space of 40 hours of operation and its pure luck i didn't lose one or both of the pins before I spotted the problem. With that MTBF the design certainly qualifies as inexpensive to manufacture but not "reasonably reliable". The replacement cap screw I put in is shorter and less exposed. The idea of allowing the pin to float was not lost on me and it still free to float axially and radially because the drilled hole in the pin is well oversize. Cotter pins, hairpins, and locking linch pins also crossed my mind. If I have a repeat of the problem I will ditch the bolts altogether and make two new pins with snap ring grooves. As you note - many ways to do the job and some are certainly better than others.The whole purpose of manufacturing is to sell a product that competes with other brands in quality, styling, etc., a product that has reasonable reliability, meets government standards and regulations, yet still turn some sort of profit. There is a lot more to it, but that's the very basic idea.
And therein lies many issues for engineering.
Remember they still have to turn a profit. Meaning if a JD of the same size is $5 less expensive, they're gonna cut $7-$10 out somewhere, maybe getting a bolt cheaper from a different supplier or whatever.
So on a loader pin you have a lot of options. The way the 525's are designed is the same as they've been for decades. Bolt through the end of the pin, and it hasn't really been an issue to my knowledge.