This is not gonna happen at all, way too much for a altcoin and the bitcoin too, I believe the bitcoin can hit a high amount but not such an high amount, that is just not in the bitcoin honestly.
$600 for any altcoin may be high to speculate but for bitcoin $6000 is reachable with all of the aspects, look at the current marketcap of bitcoin its around 10 billion and when it will be around 100 billion price can be 10 times almost and if you look at the total market size of payment processor exist right now it is near trillion mark so 100 billion marketcap is possible for bitcoin and also $6000 price is possible.