There seems to be a race to the bottom when it comes to pay across all industries. These are wages from almost 30 years ago for a middle level IT person. In 1994 a typical high end IT manager for a national corporation was around £70k+.
Edit: I just remembered that in 1996 the company I worked for paid £1k per day for an external contractor to provide Unix and IP networking consultancy services to one staff member. That went on for five days per week for about a month at least. That staff member was on about £40k.
Governments see inflation as a way of making things cheaper in real terms. Public sector wages should be index linked IMHO, but I'm always told that to do so would be "inflationary". To put that another way - Not giving people real-terms pay cuts is, apparently, a driver of inflation.
Economists have built a system which relies on the buying power of the workers going down.
The private sector is all right, but the public sector is absolutely mad. Everything is being run by committees these days which is a polite way of saying that everything is run by idiots that don't respect other people's talents. Also there's always someone that thinks that "patriotism" will somehow fill the pay gap.
When the gap was only £10-20k a few years ago, you could justify to yourself that sticking in the public sector was probably affording you some quality of life benefits.
Now the gap is more like tripling your salary and nearly everyone good has left for greener pastures. Hell, the work/life balance didn't even change much for me