Here are a few pictures of modern bike technology at its finest -- which is to say aggressively marketed mediocrity.
The area around an inset headset looks like the floor under a leaky toilet if the owner hasn't been meticulous about keeping it clean and dry. Hidden bearings seem like they should be better protected, but they really just do a better job of containing contamination and hiding problems while they really fester. The second photo shows a bearing that festered for a couple of years. It used to be a cartridge bearing, but it came out in rusty pieces.
Disc brakes need to be properly aligned and frequently checked to make sure that they're working correctly. Because the pads are in their little turtle shell, it's easy to forget about them, and hard to really see what's going on in there. An inexperienced mechanic set this caliper up so that the inner side of the caliper functions as the brake pad. Mechanical brakes aren't self-adjusting. If no one thinks to adjust the inner (fixed) pad as it wears, the outer pad eventually just shoves the rotor over against the side of the caliper. It'll be a little noisy, but it will stop you eventually.
What the hell does this mean?
This isn't a technological issue. It's just rude. It's equivalent to showing up at your doctor's office with a dingleberry. I get it. You're a mountain biker. I don't need to add your souvenir mud to the mess I already have to clean up in the workshop.
Bike componentry development reminds me of the joke about the two guys running away from a bear. One guy stops to put on his running shoes. The other guy says, "Why bother? You can't outrun a bear." The other guy says, "I only have to outrun you."
No matter how much money you spend on ultra-fancy bikes and parts, you'll never really be fast. You'll only -- maybe -- be faster than the other pathetic dorks working outrageously hard to go about as fast as a prudent driver in a residential neighborhood.