Yeah but most of the times, the items posted weren't used enough. I've got jeans I've worn twice a year which are 30 years old (passed down to me by others). I wouldn't call them BIFL because they're barely used.

I'd praise more affordable jeans I've had for 5-6 years which have been worn few times a week and frequently washed and dried in the dryer and are still in great state.

Yes, but so many times it is a item that gets used a few times a year. Just about anything will be buy it for life if not used.

Only if most of the produced items commonly survive. If one stove happened to be produced on a golden day 80 years ago when all forces aligned to make it indestructible, but the rest of the line has since blown up, highlighting that one good one isn't useful.

It's not just about how long something lasts, but how good it is. The concept of quality has been completely lost on this subreddit. Your grandmother's 40 year old microwave might technically still work, but it's a massive piece of shit compared to a modern one.

Yes, survivorship of the total population of the production run matters when determining the likelihood that any particular item chosen at random survives. So if 50K out of 100k of an item produced 50 years ago are still around and functional, that would tell you something about the products longevity. However, if you just have examples of items that have last 50 years, but aren’t considering or don’t know, how many were initially produced you can’t determine what the probability of survivorship is.