Why isn't humility included in the fruit of the Spirit?

Recorded in Luke 14, Jesus contrasted banquet-seating choice scenarios and recommended the humble approach.  

In Phil 2, Paul encouraged us to have the humble mind of Christ.

It seems like humility is essential for intimacy with God (e.g., Moses).

So, why isn't humility listed in the fruit of the Spirit in Gal 5?

Perhaps, in this mysterious collaboration with God to become like Christ, my spiritual maturity and/or intimacy with God is rate-limited by my freewill choice to humble myself before Him.  

Over the last several years, the parable of the prodigal son has become my favorite parable of Jesus.  I think the prodigal son demonstrates humility:

I will set out and go back to my father and say to him: 'Father, I have sinned against heaven and against you.  I am no longer worthy to be called your son; make me like one of your hired servants.'  So he got up and went to his father. ...

Luke 15:18‭-‬20a NIV

And we see the father's mercy and grace in response to the son's humility.  

... But while he was still a long way off, his father saw him and was filled with compassion for him; he ran to his son, threw his arms around him and kissed him.

Luke 15:20b NIV

Indeed, this is a fundamental spiritual principle/promise explicitly stated in Proverbs, 1 Peter, and James:

But he gives us more grace. That is why Scripture says: "God opposes the proud but shows favor to the humble."

James 4:6 NIV

Father, I want to humble myself before you.  No pretense or presumption.  I want to be fully transparent and genuine, no hiding anything from you- no trying to cover up anything, and no trying to make more of myself than I am.  And at the same time, I want to be totally secure in your love, knowing that nothing I can do will make you love me more or less.  Jesus, thank you for your example of a humble life, not holding on to your deity, but fully living out the life of a servant. Thank you for submitting to the Father. Holy Spirit, thank you for the opportunity to be close with you all the time.  Thank you for your presence.  Please help me remember to choose to be humble to maintain our fellowship.  I love you, and I want to be close to you, so I want to be humble.