If AI is already doing most people's jobs by then, then there will be a greater chance that humanity would be able to recover from this widespread decline in human intelligence.
AI won't solve human obstinacy, human entitlement, human greed, human short-sightedness, anthropocentric hubris, etc. I seriously doubt anything can, let alone a large language model.
AI tools are tools, like typewriters and airplanes. Problems that people cause in the world (and can but don't fix) are just that: people problems.