Hey! That's not a bad concern. I was thinking about it one day, what came to my mind was:
-We won't get salary in BTC unless it's ULTRA stable like one price f.e 1BTC=10.000$ and nothing will change it (it's impossible tho)
-Blockchain technology is NOT a new technology, it's just hot topic right now and people are able to find usage for it. I think it's a game breaker and will revolutionize few industries.
-Will blockchain end slavery? I really hope so, it has potential it depends on our will how we want to use it.

To sum up, I hope decentralized world will become a thing, although BTC is like representant but not a currency which will lead for ever (of course all of this sentences are IMO, you can disagree).