it is not for lack/want of trying

:  to be deficient or missing

:  to be short or have need of something

:  to stand in need of :  suffer from the absence or deficiency of

:  the fact or state of being wanting or deficient

:  something that is lacking or is needed

:  to be needy or destitute

:  to have or feel need

:  to be necessary or needed

:  deficiency, lack

:  grave and extreme poverty that deprives one of the necessities of life

:  something wanted :  need, desire

:  severely straining the powers of endurance