Take the other example of Belgium whose tax level is more or less equivalent but is scaling down on basically everything. People there complain that they pay a lot now, but are almost certain that when their turn come, they will not get anything.
We are in a context where you can't predict the outcome of the next election a single day before, who will trust to current generation of politician with policies in 30 years ?
Also, that's not just a question of egoism. I don't mind paying today so that people get unemployment benefit and a good pension. The problem is that if it goes the other way when I reach retirement age, I will neither receive the pension nor the year of tax cut to make up for it.