The article brought back some good memories of camping with friends - one of them brought this book and read it to us. We were all in our late 20s, no kids around. Kate I miss your awesome vibe.
It is saying - don’t wait on others to come and change or complete you; you have to make the changes yourself first.
In your situation; if you truly believe you need to stretch your skillset to be more extroverted at times, that is something you need to take personal responsibility for. You need to add to your capabilities through effort.
So I don’t think it’s really saying you don’t need others ever; it’s saying don’t look to others to “fix” you; if you need to be less introverted at times, that’s something you can work to control.
But the message for me is that we should work on ourselves first to be happy with who we are.
You've got the wedge and incomplete circle, that when fitting together just right, roll along perfectly. That becomes unstable once one piece changes.
Then you've got the end-state: two self-sufficient circles which roll in parallel, just because they choose to.
The first two stay together via a strong need, like a dipole-dipole bond between molecules of a solid. The second stay together with a much weaker, Van der Waals force, and are easily separated.
It very aptly predicts the rise in divorces in the West once women had more opportunities to be self-sufficient. I won't address if that's good or bad; I just want to compliment Silverstein on a very successful metaphor.
Your story reminded me of that feeling - so cheers!