I wish auto manufacturers knew this.

They do. Cars are engineered to fail and some models are sold even at loss to get the profit from OEM parts and service. This is also often the reason why seemingly similar parts are incompatible from one model to the next; the manufacturers are racing against the (often much more durable) aftermarket parts. If they were in the business of making cars great for the consumers, they'd engineer them strong with grease fittings on every moving joint and have all parts standardized across models and brands, differentiated mostly by car size or such (supercompact vs crossover suv vs heavy-duty truck). This would however result in cars that would be easily maintained to last forever, like some old work equipment is and that'd be bad for the planned obsolescence market model of car manufacturers.

And yet, cars still last for two decades or more if maintained properly, and are IMO some of the most reliable pieces of gear out there - I'm finding newer models to be better in that regard than older ones (but maybe that's bias on my side, I haven't driven older cars in a while now)

Yes, if maintained properly, which means swapping out these engineered to fail parts every so often, which becomes uneconomical at least in the resale sense at some point in time, because the repaired car resale value is less than the cost of repair. For instance on VAG cars, the designed to fail cash-cow parts are typically the various suspension bushings. Once such a part is worn out, resulting in a part that has excessive backlash, it'll cause prematurely worn out parts in the rest of the system it's a part of as well.

My daily driver is a 25 year old car that I'm keeping on preventive maintenance. I got it when it was 16 years old and still in pretty good shape since it was barely used and always kept in a warm garage. I've always had pretty old, but well maintained cars in order to minimize the total cost of ownership of them, and kept them running until something too difficult or expensive breaks. I never value them for what I'd get for selling them, because I've never sold a car nor planned to. To me, the car value is always the utility and TCO value of knowing the state of them via preventive maintenance repairs. Usually the failing part not worth fixing is the body, either due to a collision or rust damage.

In addition to always inspecting an used car from underneath, a thing I learned early was to replace all the cash-cow OEM parts with upgraded parts when possible. If not, at least try to have repaired parts made that are improved at the point of failure to be stronger than OEM parts, so that they don't fail the same way again. Factoring the preventive repair into the price of the used car is required in order to be sure to afford owning the car. After that initial preventive repair, it's about checking the parts stay like new, or it becomes very expensive to keep very quickly once something fails after a part's worn out.

Anyhow, look at farm equipment, mine equipment and such to see what vehicles not engineered to fail are constructed like, and I don't mean the extra robustness of the loadbearing parts for the much larger workloads they're designed for.

"which becomes uneconomical at least in the resale sense at some point in time, because the repaired car resale value is less than the cost of repair."

I think this is a common misconception about car repair economics. The question is not whether the repair cost is more than the value of the car, the question is whether the repair cost + sale cost is higher than the value of the repaired car. I like keeping cars that I know the history of, even if the car is worth <$2,000 and the repairs >$1000, because it is unlikely that I can get a $3000 car that I have as much confidence in.

And advice on identifying such cash-cow parts? My vehicle repair knowledge is limited.

Experience first-hand or via experts who repair them daily, the former can be done by owning the same car or brand for a longer while and spotting the pattern.

Prefer makes that have excellent rust protection and models with relatively low stress configuration engines rather than high performance models. The two latter are usually mechanically the same or mostly the same, but the latter of them receive much larger stresses in use and hence tend to fail earlier.

If you intend to modify the car, prefer older ones, because they have lower regulations, but this depends on the legislative area you are in as well. For instance cars with OBD-II are too new for engine upgrades almost anywhere.

OP is being downvoted for starting off on a rant, but he is 100% correct about the grease fittings.

Maybe it's that they don't care. Last transmission I rebuilt (following.factory service manual) had a Phillips fastener with threadlock on it that required destructive removal after careful use of a manual impact driver. Replaced it with a threadlocked Allen fastener.

> destructive removal

When in doubt, drill it out?