It all depends on the quality of the guitar, the quality of the playing, the quality of the gear and the quality of the soundperson. Bad sound anywhere in the chain means bad sound for a final result.

Learning to play with a guitar with a pickup is just another set of things to learn. If you can learn to play guitar competently you can learn to play an amplified guitar competently. Like anything else, you have to practice.

I agree that there are a lot of folks playing with awful sounding pickups. There are just as many playing with good sounding gear.