Even animals "self-trancend" for their family/herd. it is instinctual.
Most Humans "self-trancend" for their tribe/nation. it is emotional (+ instinctual).
But it is not really "self-transcendence" as posited here: universal and mindful (to not say "intellectual").
Self-transcendence is on the side of the hierarchy of needs, though admittedly a person isn't going to be very good at self-transcendence if they are starving or aren't educated. I think this drive of self-transcendence guides many people whenever they are at the various levels. Though admittedly some people get all the way through a Ph.D. without really having a sense of meaning or purpose, I think this kind of trajectory is in the minority and most of us mix it up a bit.
All aspects of the pyramid are present at all levels, what the pyramid represents is what you have to free yourself of in order to truly and wholly endeavor in each stage.
You can act with self-transcendence even if you're starving, but you can't direct as much thought, time and energy towards it unless you cover the underlying needs.
This is all well and good, by my psychological need for esteem, and to a lesser extent love/belonging, is so much less that I ignore its pull to large extents (and have even been viscerally repulsed by praise through portions of my life). Maybe that's why I've not been all that facile at Captaining my own destiny in this world.
I think the pyramid is a bad shape.