Yes, it is true that many vendors today do a very careful analysis of what their customers really want: A cheap product, a high-performance product, or a very reliable product. And they make a very conscious decision of what to build and sell, based on their understanding of what their customers want. Building a real-world product requires compromises there. The old joke "good, fast, cheap, pick any two" is a quick summary of those compromises.
Apple is actually a very good example. They know what most of their customers want: (1) a super easy user experience, seamless and efficient, while you stay in the "walled garden" of using only Apple products for all your computing and communications needs. (2) Features, such as very light weight, high display resolution, good sound. (3) Cost is not a big issue. What typical apple customers are not interested in is long-term survival: typical customers replace cell phones in 1-2 years, and laptops in 2-4 years. Most large corporate purchasers of laptops have policies that automatically replace employee laptops in a few years; at a previous employer I had to fight to keep my 3-year old laptop for another two years.
Apple is very good at servicing the needs and wants of that market segment. If they can save or 30g, 1cm^3 or $10 by gluing the battery in, that is a good tradeoff for them and their users: The fact that the cellphone becomes obsolete after 2 years, or that the battery replacement on the laptop is a $300 repair at the Apple store instead of plopping in a $100 spare part is not important to their customers. Most of the time they make the right choice; occasionally they screw up. For example, the laptop with only one USC-C connector was a mistake, and they figured that out (too late unfortunately) and fixed it in the next generation. Another example is the new Apple MacbookPro keyboard with the touch bar: While it is really good at serving a large segment of their user demographic (namely those who want a thinner and lighter laptop, and who don't touch type and are helped by the F-keys changing their labels depending on what app is using them right now), it gets other users really mad. Unfortunately, I'm in the camp of the other users: I'm an old piano player and rely heavily on mechanical keyboard feel to type fast and accurately, and I touch-type the F keys blind (usually in emacs), so having them move around and not have tactile feedback really screws me up. So Apple, in their (correct) drive to serve their core users better, is upsetting a fringe user. So far I'm OK with this, because both at home and in the office I use my laptop with external keyboards, but in airports or meeting rooms I'm not a happy camper.
Dell, HP, Asus, Chromebook and Alienware also make competing laptop products. They are engineered for different user expectations and wishes. Some are cheap, some are fast, some are sturdy and reliable, some integrate well into corporate management systems, some are compatible with FOSS software, and so on. In reality, they don't actually "compete" very much, because they all serve different segments of the market.
The important thing is this: If you are not the kind of user who fits the profile of what Apple (or any other vendor) is trying to serve, then don't buy that product. And if you bought the wrong product, then don't get upset (in particular not in public) about the fact that it doesn't fit your desires. This goes for many posts in this thread, where posters are needlessly and wrongly upset that Apple products don't do what they want.
Now where I agree with your comments about bearings: Sometimes a very small change to a product (a tiny cost or weight increase, like a better bearing on cooling fans) would make the product quite a bit more universal, and capable of serving a wider user base, or giving the core user demographic additional value or function. Sometimes manufacturers do too good a job of tailoring their products at specific target markets, and forget that a little bit of universality would actually have a payoff too.
