This sounds to me like a combination of survivorship bias and cost preference.
You see the resilient things at your grandparents' house because those are the only things that have survived. All the poor quality things they purchased over the years are gone by now. Also, you and your parents probably favor lower-cost items (as do most people these days) over longevity. This may simply not have been possible in your grandparents' time, pre-globalization. It's still very possible to get high-quality and long-lasting goods (the buyitforlife subreddit is a good starting point), but you're going to pay a lot more for them than most people are willing to in comparison to the "replace it when it breaks" mass-produced-in-China goods.
You see the resilient things at your grandparents' house because those are the only things that have survived. All the poor quality things they purchased over the years are gone by now. Also, you and your parents probably favor lower-cost items (as do most people these days) over longevity. This may simply not have been possible in your grandparents' time, pre-globalization. It's still very possible to get high-quality and long-lasting goods (the buyitforlife subreddit is a good starting point), but you're going to pay a lot more for them than most people are willing to in comparison to the "replace it when it breaks" mass-produced-in-China goods.