fall by the wayside
1 fail to persist in an endeavour or undertaking.
2 be left without attention or help.
☞ In sense 1 the phrase alludes to the biblical parable of the sower in Mark 4:3–20, and in particular to verse 4: 'And it came to pass, as he sowed, some fell by the way side, and the fowls of the air came and devoured it up'.