That is a hypothetical situation which seems to me like it would be pretty unlikely.
Banks aren't talking about deplatforming coinbase, for whatever reason, therefore it is useful.
The whole "what if the government/banks banned Bitcoin!?" Is a pretty silly hypothetical, to me, because if you look at what these groups are actually doing, you will see that they aren't doing this and aren't really trying to do so!
The only reason why I am sceptical, though, is because I have heard these same arguments, about how the government will ban Bitcoin, for 6-7 years. And yet it hasn't happened yet.
So it is totally possible that this time is different. But I just feel like, I need to be very sceptical about these arguments, until they actually happen. Because I heard them before, and those people were proven wrong.
But you are right, in that it is very possible that maybe this time is different.