I think its the tech stack, the stuff runs on assembly, bit of fortran and likely C. You simply cannot match that level of reliability these days, because people started to forget how to do that...
Look at cars and everything else...
In the 1970s, there was a distinction between "machine language" and assembly language. Assembly (or assembler) language is the symbolic source code that a programmer would use. Machine language is the binary dump of the actual text segments that the CPU directly interprets to run.