The governance model for the income trust is significantly different from that for corporations. You're comparing apples and oranges. The governance model in income trusts is such that, yes, the majority of the cashflow is paid out to the unitholders.
If management wants to pursue an acquisition opportunity, a development opportunity, or a major capital obligation, they must go back to the capital markets and fund that directly out of the markets. They have direct accountability to the capital markets.
In a corporate model, they retain the cashflow as retained earnings. In a lot of large corporate entities, this essentially becomes the hobby fund of management. They don't necessarily have the same direct accountability—