In the long run, I don't think so. If we get to a situation where there is one or two entities in easy-for-governments-to-reach places and they hold some very large amount of bitcoin, it becomes much easier for that government to push for changes in the protocol.

If Coinbase had 10 million btc and they announce that their node is going to run hard fork x, and they are going to dump the side that is real btc, it would put a lot of pressure on the people who hold real btc. Could it weather that kind of pressure? During this time we will all have built bitcoin into our lives with a certain concept of the price. Massive dumping by such a custodian could lead to a lot of woe. How many people in this example would go along with coinbase's fork because they can't survive the dumping?