Nothing is going to remove Bitcoin from darknet. It is still the main crypto used there:
http://www.coindesk.com/bitcoin-remains-most-popular-digital-currency-on-dark-web/There is already too much infrastructure made for bitcoin in darknet. You have blockchain exporer there, escorove services, bitcoin exchanges, mixers, scammers, etc.
None of the ppl involved in these services, e.g., mixers, will allow to have any other crypto to take their mixin cut.
Everybody could add another service over there. It's not regulated as in "needing a licence signed from these former infrastructure providers". A new service can just pop up at random. Overall, they tend to vanish at random, too.
Back on toppic, the yearly spring season pump might have been widely anticipated, to many people prepared can make that difficult terrain.