Electron Binding Energy

Why are electrons so easily lost from atoms?

If a classic electron and proton existed within a hydrogen atom, the
energy necessary to completely ionize one mole of hydrogen atoms would
be great:

Approximating (not based on reality) that previous to ionization the
maximum distance between the electron and proton is about equal to the
molecular diameter of hydrogen 5x10**-10 Meter:

Potential Energy = Kqq/r x Avogadro constant

Coulomb Constant Electron Charge Distance Avagadro
= 8.98755x10**9 x (1.602x10**-19)**2 / 5x10**-10 x 6.02x10**23

= 2.7x10**9 Joules = 7,500 Kilowatt Hours.

This seems a lot of energy to ionize 1 gram of hydrogen.