"Going Galt" appears to primarily be a fantasy scenario. People largely tend to consumption rates which are smoothed and that factor in long-term expectations of income as opposed to marginally increasing rates that follow short-term signals like a linear input-output device. So it seems that tax burdens alone are not enough to cause massive "dropping out of society", as rational actors have determined that participation in consumer society in light of regulations and other externalities is still preferable to the costs of off-the-grid living. Not that taxation can't cause disincentive, but it's more complicated than just that.