I suppose that all depends on the definition of "success".
My definition of success is perhaps modest to some, but it is still far away:
Bitcoin being the protocol and the coin of the internet realm.
If it achieves this, it could well become much more, but this is the success for which it is designed.
Knowing your way of thinking, yes; it is a modest target for something that incorporates so many different things in just one package. Maybe the "beginning of success" would've been more appropriate.
Side chains are absolutely essential if you want BTC to evolve and fulfill such a goal.
Without side chains, you can assuredly kiss that hope goodbye, because for example we can see now that Bitcoin as currently designed is not decentralized because it requires all this politics on the issue of scaling.