Why are plants and the bottom of the energy pyramid?

An energy pyramid shows how much energy is flowing through a food chain/web or just a meal. The plants collect energy from the sun, so at the start, they get the most energy. Then, herbivores eat the plants. They still get a good bit of energy, but less so because the plants have already used it to make glucose/their food. Then, predators/carnivores eat the herbivores. They get much less energy because the herbivores have used a lot. The "top" predators get the least energy, because so much of the energy has been used up mostly.

That is also why there are more plants than herbivores, more herbivores than predators, and more predators than "top" predators. Because the top ones get the least energy.

So, the plants are at the bottom because they start the whole eating frenzy, and because they start with the most energy.