Why is this wrong? To succeed in the new economy, workers will have to learn throughout their careers, adapt to changing circumstances, and have self-motivation.

Answer 1

The first phrase ("To succeed...") is correctly placed to modify "workers."

The error is probably in the series, so consider this:

... will have to ...

~~learn...
~~adapt...
~~have...

The only thing I can suggest is to change that last have to a real ACTION verb and rephrase as needed. The verb have is more of a "mental" thing, not something that someone DOES.

However, I wouldn't mark this sentence as incorrect for parallelism.