I think relating burnout to learned helplessness registered as dismissive to you - it definitely isn't. Depressive helplessness/burnout/learned helplessness all have a lot in common; GP was apparently just making that connection. They probably share some very similar biological mechanisms.

Point of relating it to learned helplessness is that companies may structure their work, or assignments, or team structure, or culture, expectations etc in ways where employees feel nothing is getting accomplished, they have no autonomy, workload stacks up, and eventually they feel nothing they do can make the situation better.

They are not setup such that applying more effort causes workload or problems to get smaller, or where progress is made. They learn that the situation is helpless.

Now there's some fuzziness around whether this realization is maybe the end of the struggle for some, where they stop burning themselves out and just give up. But they would need options; quitting or having alternative employment to go somewhere else. If not, they'll be in a bad spot.