In my view bitcoin is already a success in that it allows anyone to transact with anyone without a middle man. What you are describing is mass adoption so let me focus on that.

Like many questions about bitcoin we have already seen what happens. When bitcoin hits a new ATH many trade their precious bitcoin for crap. And each time this happens and bitcoin rises from the massive drop in market price again people kick themselves for their stupidity. What we are witnessing is people learning hard lessons. People talk a lot. I have no doubt that many will sell their bitcoin when it hits another ATH but there are many ways to exchange value for value. This does not mean selling it all for fiat. That said, some people will never learn. We can't help them.

Here's another funny thing about your scenario to think about. If we enter a world where governments and large companies have stronger hands than bitcoiners we are gonna be living in an upside down world. Many of us believe the governments and banks of the world are playing with fire. They are playing a game of musical chairs and when the music stops a massive amount of the world is going to be hurting overnight. This may not happen in the next 10 years or even the next 20 years but it will happen. And when it does the world will need a money that can't be centrally controlled by evil bankers. That to me is the end goal of bitcoin. To save us from the evil system.

Those that understand bitcoin's value will not sell it when it is valued at whatever. Those that understand the value of something are rewarded for their foresight. So yeah, I consider that a "success".