Revelation 20:14, The End of Death and Hades

Then Death and Hades were cast into the lake of fire. This is the second death.

//In my book about Revelation, I assume that this verse symbolically presents the end of death … that death has been conquered. Hades, the holding place of the dead, is therefore no longer needed. It is emptied and discarded.

There is, however, a deeper way to read the verse. It is by referring back to the four horsemen, where Death and Hades are first introduced as villains:

So I looked, and behold, a pale horse. And the name of him who sat on it was Death, and Hades followed with him. And power was given to them over a fourth of the earth, to kill with sword, with hunger, with [disease], and by the beasts of the earth. –Revelation 6:8

Clearly “Death and Hades” are still to be understood symbolically, but does this change the meaning of their destruction?  Is it only the sword, hunger, disease and wild beasts that are conquered? Will people still die of old age after Death and Hades are conquered?