Why is an ecosystem still healthy although there's still a lot of consumers in it?

because it is a sign that there are more producers for the consumers.

Explanation:

An ecosystem consist of the abiotic or inorganic components, the animals[consumers], the plants[producers] and the decomposers. An ecosystem simply means the environment of organisms that are living together and the way these organisms interact with another.

The producers that is the plants are the ones manufacturing food by themselves either by photosynthesis or chemosynthesis and the consumers are the ones relying on the producers for food.

The ecosystem is still healthy even when there's still a lot of consumers in it because it shows that there are come producers that is to say the producers are more also. If this is not the case, then the ecosystem will not be healthy as the consumers will eat the producers until the producers will not be enough.