Everyone else has great points about complexity, but there is an additional issue which is the constant desire for change keeping products from being refined and perfected.

Any product will have small changes that improve it, like reinforcing points of failure specific to that design. Let’s take a kitchen knife, the kind chefs use. Some manufacturers have the exact same model produced for decades, with ever so slight variations on angles, handles, and so on as they refined design. Now they are high quality if they keep the production going, and that is something that has no moving parts! These knives continue to sell because they are used constantly, can break or be damaged, and new restaurants open all the time requiring a constant supply of knives.

The home knife market does not have the same pressure for reliability because people don’t use them all day every day like a chef. Instead, companies are constantly changing designs to sell new versions to the same over saturated market that prizes form over function. They change the handles slightly, make a change to the blade, and sometimes these changes make the knife worse but they can slap a ‘new and improved’ sticker on the label as long as something changed.

The same thing happens with technology except complex systems have even more refinement needed while the companies are also trying to change things just to change them in the pursuit of the ‘new and improved’ market. Moving menus around, changing orders of things, making things look flashy are all side effects of tech being afraid of selling the same thing for an extended period of time because people want something new and shiny to replace what they had. Time and effort is spent on changing things, and it is hard to do bug fixes while also creating something new that might make a bunch of old bugs obsolete. Oh, and they will also be spending their time trying to patch critical vulnerabilities, because that might keep someone from buying their next thing.

So all the effort going into changing things, often making them worse if they happened to stumble into a useful design already, and they put all of their focus on that change and vulnerabilities so they don’t have time to fix usability issues or do the things that would make their product better because why bother as long as people are buying? Anything someone who is knowledgeable about being fixed is unlikely to be a priority because the regular user probably hasn’t even noticed and they are the ones who are going to buy the next version. That is why things like bluetooth continues to suck, because it works well enough to sell more things and doing it right would take more effort. The handy feature that you used to like being removed? They felt it needed to change just to change and whoever provided input or feedback came up with this instead.

Oh, and all of this was just talking about available time spent doing things but on top of that they want to spend as little as possible so they get the cheap parts that are made by companies who also make a product just good enough that they get more customers to buy their parts for as little cost to produce as possible.

TLDR: market pressures favor changing things constantly which introduces more design flaws and capitalist pressures focus on revising designs to sell more and security flaws so as long as it sells it doesn’t matter if it has shitty usability and minor flaws are never fixed