The main message was that the FCA will support LIBOR up to 2021 but not beyond and encourage the market to start the transition to alternatives today.
Ending the publication of LIBOR by 2021 may be possible. Replacing it in earnest by something else by that date is a completely different task. Swaps have maturities up to 50Y; if you stop publishing LIBOR, parties to the contracts have to use the fall back in the contracts. If you want to replace LIBOR by one new benchmark, you need the agreement of all the parties involved, it means each party to each and every single contract referencing LIBOR has to agree individually. There seems to be an agreement with this in the terms of the speech. I was happy to see that the terms "challenging " and "extremely difficult" were used in relation to the change of benchmark.
Even if the "L" in LIBOR means London and LIBOR is the king of indices, LIBOR is not an hereditary monarchy.
The King is dead, long live The King!is not a proclamation that is appropriate. I would say
The King is dead, the Game of Thrones can start.