With that said, I'm not sure why both our arguments have to be mutually exclusive? Why can't it be that things are being planned for obsolescence + we're living too long?
Regarding your last point, let's say that you did know you were going to live to 100, I think you'd be hard pressed to be able to afford a lot of that nice stuff which would serve you in the long run without working into retirement age (unless if you just happen to very wealthy).
I earn a relatively high salary and even if I was making the most of my retirement contributions and considering compounding, it would still only last me by 90 without requiring state assistance. And most importantly, that's if I were to maintain my current lifestyle, which includes buying the cheap shit I can afford (in part so I can keep up with funding retirement).
I couldn't imagine how much harder it would be for those on an average salary.