The real question is: Do you need to understand it fully for it to improve your life?
For example, if you're in fundamental science (or generally a fan of reductionism), it for sure would be nice to understand the universe instead of just having access to an AI that can comprehend it. But to the majority of the population it only matters that someone (or something) understands it enough to make it useful to others.
Understanding everything fully is futile. But there are many many many things that by understanding you improve your life. So, I feel the question is... not useful, I would say. Yes, you need to search for things that if you knew them you would improve your life. No, you can not know them all beforehand. Yes, there are such things. There always are.
They only improve your life if you actually work on something that you yourself are trying to improve. Most people are fine with the status quo, so if something like LLMs can take over the understanding of complex tasks, they won't even notice, except for the fact that more of these tasks will get done.
There are clearly things to understand more than just the immediate stuff you do for work. I think most people are thirsty for understanding, it's just... many times it's in other domains than you expect.
For example, if you're in fundamental science (or generally a fan of reductionism), it for sure would be nice to understand the universe instead of just having access to an AI that can comprehend it. But to the majority of the population it only matters that someone (or something) understands it enough to make it useful to others.