If only my fridge had such a lifetime...
The example of the light bulb cartel that had unquality assurance, spot testing, and a formal structure of fines and penalties for any members who made too long of lasting lightbulbs is just hilariously dystopic.
But one of the major reasons is probably that products have become much more complex. A 30 year old fridge had few components that could break. Modern fridges are much more complex (because extra features sell well), thus more stuff that can break.
In our society the brilliant engineer is not the one who makes a thing that last for 50 years, but one that lasts for just long enough to avoid damaging your brand image, and also fails in a way that makes the consumer more incentivized to buy a new thing than try to repair their current one. The guy who came up with the idea of slowing old iPhones "to save battery life" is who the bonus+promotion is going to.
One of the biggest problems that has to be understood is that there is every incentive for money-driven governments to actively support planned obsolescence. Planned obsolescence drives factors that we believe are indicators of a strong economy, like GDP. If people were able to stop endlessly buying the same things over and over, the "economy" would take an absolutely massive hit. And with it there would also be declines in employment, tax revenue, and everything else. This is one of the many examples where the socially detrimental relationship between government and big business isn't just based around corruption.
Of course our system, for all its flaws, also has its benefits. Like the old Soviet joke goes, "It may be true that the Americans have the biggest skyscrapers, but we have the biggest transistors!"
I guess all other things being equal, I'd still rather have something fully functional replaced because there's something new and preferable, than having to replace something that just breaks. But if the cost of the "lifetime" good is a lot more money due to its quality, than the replacement costs of the less durable good that you'd replace anyway due to improved function, it becomes harder to say. Even harder given uncertainty about all of the variables involved.
In the early 20th century GM wanted to sell cars but the problem is that the market was already saturated with cars that were well functioning and built to last. And so they needed to develop a way to convince people to buy another thing that does effectively the same as some other thing they already own. And so instead of working on creating better cars, they worked on marketing, persuading people that round edges were better than square were better than round were better than square. Hey, look at this new color!
I quite like the quote referenced in Wiki, describing this all as "the systematic attempt of business to make us wasteful, debt-ridden, permanently discontented individuals."
[1] - https://en.wikipedia.org/wiki/Planned_obsolescence#History
Yes ... away from Earth at 38,210 mph