is there a better practical alternative of introducing new currency without this injustice inherently build into it?
Promoting fingernails, hair, and skin as money?
That was a joke, but my point is that you don't get money for simply existing, you have to do something that other people value in order to earn it. The original adopters (miners) of Bitcoin were doing something, securing the network when it was brand new, regardless of how valuable other people think it is. Who has the right to come along and say, "Hey, give me some of your labor", simply because they feel that past labor shouldn't have as much value as it currently does?