The basic reason that investor capital has a liquidation preference is that if it didn't, the founders could raise $X million on day N, then since they hold the

The basic reason that investor capital has a liquidation preference is that if it didn't, the founders could raise $X million on day N, then since they hold the majority of voting rights, declare bankruptcy on day N+1, and split the majority of the invested capital among each other. There are ways around this, such as giving the investor a veto on bankruptcies and reorganizations, but the time-honored solution is a 1x liquidation preference where the investor gets their capital back in a bankruptcy.