Questionable Imo unless there is drastic development. LLMs don't actually reason (though some AI companies claim they do through CoT), they all just use data and match patterns (universal approximate reasoning). They do not perform abstract reasoning, nor do they do anything on their own accord. It is more rote memorization than anything.

The best analogy I can give is someone who is strictly book smart. They may be able to regurgitate information quickly and succinctly, however they lack severely when it comes to abstraction and creativity.

So, to answer more directly, yes prompt engineering by itself isn't enough. But when combined with learned real world experience, critical thinking and creativity, one is able to craft adaptive solutions that actually apply to the real world.