I don't think its ever been documented, but in the old days many Families had a monthly stipend in place that their members contributed too. I think it was more common than uncommon within the various borgatas.

Profaci was not the only boss that had implemented a "tax" so to speak.

And in response to your other statement, I think "greed" is indeed why most of these leaders have fallen. Either directly or indirectly, their greed and drive helped get them to the top. But in the end spelled their doom!

The more intelligent and less greedy bosses mostly died in bed instead in a jail cell or the gutter bleeding out.