I have the feeling that Bitcoin will soon give up it's place. First to etherium and then to other new coins. This change is maybe happening at the moment, but I think it is long overdue.
And for doomsday Bitcoin is the exact opposite of gold. I mean, one other coin supercedes it and all value is lost almost instantly.
Bitcoin will always be around as it was the first kid on the block and the massive amount of infrastructure around it. I agree, Bitcoin will loose top spot but it will continue to go up like the rest.