Actually, zooms are harder than primes, wide harder than tele (yes, even in very long lenses like >400mm).
400mm prime Nikkor has 11 elements, 18mm prime 13 elements, and so on. However, the distortion management and the need to bend the light becomes much harder for wides than teles. Take a look at some diagrams of wide and you will be amaze by how much they have to bend
OTOH, long lenses, though don't have to bend so much, whill have the problem of size and weight of elements to content with