It's pretty well accepted that government grows significantly with development. There's an actual theory behind this, though I can't remember whose it was. Anyway, what I've been musing on is whether the state has actually enlarged that much if you think of it in terms of disposable income rather than total GDP. After reading Braudel, something that really struck me is how much of income used to be devoted to simply staying alive. This percentage has declined massively with time and is continuing to do so. So if you think of the cost of government only in relation to the percentage of GDP left after the cost of the food, clothing, and shelter necessary for survival are taken out, is the state that much bigger of a slice of GDP than it was in earlier times when the simple cost of staying alive was a significant portion of GDP? Maybe the state actually occupies a fairly constant share of disposable income and it is disposable income that is expanding as we develop?
I'm sure someone has done these numbers, though I haven't seen them. Just something I've been musing on. Though if you really wanted to set about calculating this you'd need some way to deal with the changed role of medicine in daily life from the past and longer life expectancies. Still, might be an interesting angle to look at the state's size from.