Actually PacBio does just that to get better a better error rate. They basically have X amount of sequencing that can be done. You can spend that X however you'd like. If you want a sequence that is X long, you'll have a higher error rate. If you want a chunk that is X/10 long, you can circularize it, and thus sequence it ten times. This gets you better accuracy with the redundancy. DNA is pretty robust.

In practice though, even with these "circular consensus sequencing" reads, the error model is significantly higher than other technologies.