Most of us have witnessed in wonderment the voracious learning of infants and toddlers. They are virtual sponges of learning. Similarly, we see children enter the primary grades of school eager to acquire new knowledge and skills, sponging up the learning at warp speed.
Children somehow seem to lose their zest for learning as they move through the normal and formal schooling processes. (I've argued for years that we educator types are culpable in that de-energizing of the learning desire - but that is for another conversation.)
As children graduate high school most move into the world of work (becoming a slave to the almighty dollar) or the world of college, then work (eventually becoming a slave to the almighty dollar). In both instances, the associated trend seems to be a relentless diminishment of enthusiasm for learning.
There are exceptions, however. You know them. They're the ones who are always dabbling in something new, tinkering in a field for which they were not trained, struggling to learn a new language, taking on roles that push them way out of their comfort zones, exposing themselves to experiences/people that are novel and stimulating.
It is great fun to engage with those forever sponges. They inspire us to keep on learning, too.
Possible epitaph: "Sponge, to the very end."