Who governments really care for?

I am always intrigued that politicians who retire seem to do quite well for themselves. One might assume that those of the right may come from from fairly wealthy stock but it seems more across the board than that. Even Hawke, who one might assume came from a modest family background, having been a son of a preacher-man and a Trade Union boss seems to have done well for himself. Keating, too, from a modest background seems to quietly lap up the lavish lifestyle.
One of the factors that came up recently in the ongoing debate about teacher's salaries in SA is that if politicians were being paid now in relationship to what they were being paid in the 1980's with respect to teachers' pay then their salary would be half what it presently is...that is, in the 80s teachers and pollies were paid about the same, now the polly earns twice as much.
. Now am I thick...or what. I just don't get this. At a time of wealth and economic success I don't understand why those who benefit most from such success should benefit even more.
The PM suggested that the go-getters and the successful should be rewarded and this would be good for the economy....I don't get this. We should make the rich even richer, there is no guarantee that that would make them bigger consumers and thus enhance the so called "trickle down effect" it actually seems more likely that they would just grow their wealth.
When we see also the obscenity of single parents being forced out to work and being $100 a week worse off I just don't get it. some articles here and here and then again here....

Surely the whole point about having an across the board value added tax which we call GST is that it reallocates the tax burden. If we were going to alleviate the tax burden why not do it across the board and reduce the rate even 0.1% That way everyone would share.
If that is not acceptable then why not reduce Petrol Excise which would also benefit everyone, and advantage commerce and industry.
But that brings me back to my title question: Who do governments care for?