Life is not all fun. You need to learn how to buckle up and just get it done.
Teacher: "today we're going to learn about the three types of rocks, and the quadratic equation."
Student: "what for? I've never seen an adult discuss or use that in real life."
Teacher: "you might need it some day, and its part of the curriculum."
Education should attempt to somehow tap into that as a core motivation, though that will surely not be enough or good for everyone.
But learning is work, and there is no way around that.
True learning, and curiosity-driven learning, boosts dopamine, hence most learning in modern society should be inherently "pleasurable". Of course this excludes hard lessons we have to learn through painful experiences.
Even really difficult learning, like at the Masters - phD level, the painful parts of learning should constitute a small percent of the person's overall learning.
Children are often accused of being unmotivated or lazy, but these are usually accusations from boring adults who can't see the magnitude of their error. A child will focus on a video game for hours, even a difficult one, and will still remember the information a week later. But give a child a boring and pointless video game, with no specific goal or accomplishment, and no one will play it. This is why the quadratic equation has become such a meme among "anti-schoolers". It's the epitome of pointlessness for the general population.
Probably most people. 6 hour days, lunch provided, recess with your friends, no real responsibilities. Sounds better than most jobs.
Rocks are easy to turn into fun since they're physical things and you can go over knapping flint, etc.
If one chooses the modern life, then they're stuck within the constraints of society. You could be nearly self sufficient, but that would be even more difficult.