Psalm 79

The use of נצח, frequent in this series of Asaph psalms and translated forever in the KJV and I expect many others, leads me to rethink traditional translation of לַמְנַצֵּחַ - to the leader or to the choirmaster. Why do we not follow the Septuagint 'eis to telos' or whatever that suggests - regarding fulfillment or concerning the end? Are all the 'leader' psalms eschatological - or would they define a new word about the end?

A Psalm of Asaph

O God the nations have come into your property
they have defiled even the temple of your holiness
they have made Jerusalem into a heap of ruins
they have given the corpses of your servants as food to the creatures of the heavens
the flesh of your holy ones to the living of the earth
they have spilled their blood like seas round Jerusalem and there is none burying
we have become a reproach to our neighbours
scorn and ridicule to those around us

How long יְהוָה will you be angry?
will your jealousy burn in perpetuity like fire?
Pour your heat O God on the nations who do not know you
and on kingdoms who do not call on your name
for he devoured Jacob
and his home they have devastated

Do not remember against us the iniquities of former times
with haste let your tender mercies go before us for we are greatly distressed
Help us O God of our salvation for the word of the glory of your name
and rescue us and cover our sins because of your name

Why should the nations say
what has become of their God?
let him be known among the nations in our eyes
the revenging of the pouring out of the blood of your servants

Let the groaning of the prisoner come before your face
for the greatness of your arm preserve the children of death
and return sevenfold to our neighbours in their bosom
their reproach with which they reproached you my Lord
and we your people and the flock of your pasture will render praise to you forever
from generation to generation we will recount your praises