Everything is replaced eventually.
That's possible but the question is when?
That's easy. As with all things, when something better comes along bitcoin will be replaced.
The technology, computer science and programming world doesn't sit still in a vacuum. It won't take as long as people believe.
Who will take over then, I guess Ethereum has a greater chance, it was my bet because I believe in the team behind ETherem and Vitalik was a genius man, he has the passion of what he is doing. If you compare the price there is a big disparity since the adoption of bitcoin is bigger and wider but as you said there will be a change in the future so it makes sense if I will hold some alts to prepare for that time.
Why does it need to be something connected to the current system of Bitcoin or all the script coins? It could be something completely different or unimaginable at this point
I conceptually agree with this point
Just like before Bitcoin it was impossible to imagine a decentralized currency circulating in a trustless network and built on the blockchain technology (even this technology itself was completely unfathomable merely a decade ago), it may be as impossibly to envisage the next stage in the evolution of money. In such cases I always advise people to watch the movie
In Time to get a glimpse of what a future money could look like and how different it might be from what we are familiar with
Bitcoin will always be respected and will never go away. But as in above, as a practical matter its just a matter of time. Probably sooner then we think. Dont forget a billion just took a position it Tezoz. He could turn the industry on its ear with one announcement. And they are not the only ones. The 2nd wave is upon us.