Tech and people versed in it were not common (to people outside tech) and so the high salaries would reflect that. Now is not the case. It was always going to be temporary. As people become acquainted with tech people, the magic vanishes, you see the code behind the pixels. At the same time, tech people themselves did cause this by making tech easier to understand and manipulate.
It's like a magician, the first few times, it is enticing and mysterious but after a while it becomes ordinary. Tech wizards are just like that.