The speed of light is a significant limitation at these kinds of scales. It's not just a massive pile of wiring and magnets etc, it's a massive pile of wiring

The speed of light is a significant limitation at these kinds of scales. It's not just a massive pile of wiring and magnets etc, it's a massive pile of wiring and magnets which kicks particles around a race track the size of a small town, with absolutely insane timing precision before dumping them into targets the size of buildings, all generating unimaginably huge volumes of data which have to recorded in nanoseconds.