Well futex based high performance mutex support which is 400x faster than what existed back when 4MB systems were sold. A Constraint solver that doesn’t deadlock, support for a boatload of functionality that didn’t even exist back then.
And most of the size comes from -O3 compiler optimizations that didn’t exist back then and if you build with -Os it is about 512KB of a memory footprint which is smaller than SysV out of the box on Debian. So it is snappy on a 386SX with 4MB of RAM if you go the gentoo route.
People use SystemD because it works better than what came before it and it will be replaced when something actually better shows up. No one happens to have found a generally better solution yet.
OpenRC, Gnu Shepherd, runit and S6 are available for people who like them better but don’t assume that they are generally better for someone else’s use cases until you know what they are.
Well this is how that technology is going to play out. For the first couple years it will be extremely helpful, to the point that the users stop depending on their own internal memories and their brains start pruning that functionality out. Then generative AI will be used to fill in missing details prior to the start of using them. And then they are going to slowly start feeding more and more lies until they are cheerful about being slaves.