I don't know about ownership in the US.
The European hotels are franchised and often acquired after buying another chain (e.g. many Ramadas are now Courtyards). So Marriott had often no (direct) influence where a property is located and if there are several at the same place.
The properties are independent and have to achieve their own profit. As long as a property is successful, there's no need to close it though another Marriott property is in the neighbourhood.