One of the problems I see when the phrase planned obsolescence is brought up is the vast difference in the examples. Light bulbs, cables, tools, laptops etc.. it makes it almsot impossible to compare these.
Different products have different uses, different "duty cycles" (how often does one use/move a USB cable to charge a phone, vs a HDMI cable that sits behind their TV static for years), different enviroments, different operating parameters etc.. Add to this that pretty much all products - save a few niche ones - have markets that cater for a wide range of budgets. Holding up the most high-end of one products, and comparing it to the absolute lowest is silly.
Example: light bulbs, LED or otherwise.. Outdoors or indoors? mounted down or up? Turned on/off how many times a day? On for how many hours at a time? Humidity?
Other things can further muddy the waters making such discussions hard to draw conclusions from.
For example: one could assume that generally, with products that have several "teirs" of quality based on price point, the higher the price - the better the "quality" and therefore, presumably the greater the chance of that lasting longer. But with certain products that are considered high-end (for example, Apple macbooks), they are marketed towards those who have a higher disposable income and are more likely to "upgrade" or obtain the latest gadget, meaning the lifetime of their product - for that particular demographic - can be rather short. One could easily argue this is planned obsolescence, and perhaps it is, but is it a conspiracy? The engineers are after-all meeting their spec - which includes the way their consumers will use the product.
Designers could then take this into account and improve functionality at the cost of longevity. Reducing cost could be done, but then it would no longer be targetting the high-end market. Lifespan is part of the spec.
And the much greater range of quality we have these days makes many points about "things were made to last" somewhat moot, as there were often very few choices in quality, if at all, so of course there were more products that lasted longer - if half were cheap and failed in a few years, the other half were the "high end" and lasted much longer.
Again I'm not claiming that planned obsolescence isn't a thing, I've no doubt it is - making things last forever isn't a great business model (unless that is the entire point of your product), but it is very difficult to know how much planned obsolescence there is when there's little in the way of similar operating conditions.