What do you mean how often, that is a foundation for the most successful economic model in humans. Some may not be discarded, but they will never get enough credit compared to a clueless head with a $1M smile talking to clueless heads with $1B wallets. We should thank god/nature that people who understand and do things exist in our species at all.

the people you need for the revolution are not the same you need after the revolution.

It only works when idealistic people don't know what awaits them (hence the "middle management" layer in most companies).