First they grow and grow and grow. Reform is occasional and minor (at best), eventually they get so big and bad that a crisis forces real change.
The state is then transformed into a lean mean productive machine. Which starts to grow slowly and the process repeats.
Of the top of my head I can think of Sweden, where a crisis forced massive reform and now it's almost ready for a crisis again.
And Great Britain in the 1970, crisis -> Thatcher -> prosperity -> growing government -> less prosperity -> coming crisis.
Guess where the US is in that cycle.