Why, when grounding, almost all of the body’s charge goes into the ground?

When any two bodies come into contact, one of which has a nonzero charge and the other is neutral, a redistribution of the charge occurs, and part of it leaves the charged body to a neutral one.
To ground a body or an electrical network, that is, to lower the voltage level in them to a safe level, it is necessary to connect them to a certain body capable of taking on such an amount of charge so that the total voltage drops to a value close to zero. If the voltage level is many times higher than the permissible one, for grounding a body is needed many times larger than the one to be grounded.