I believe that someday all digital assets (like stocks) will be tokens on a blockchain. Maybe not Bitcoin's blockchain, but a blockchain based on that innovation and Bitcoin will still be the underlying store of value for this new economy.
That's generally the direction we're heading. People might not realise it yet, but there's an upside of doing it that way, and partly it has the same reasons why Bitcoin has, and will be successful. I think it extends beyond even that, and the Blockchain will be continued to be used for all sorts of things. Obviously, when I say Blockchain, I mean it like you did; a Blockchain, and not necessarily Bitcoin's Blockchain.