A computer finding a solution to cancer, maybe.
But solving climate change and world hunger? We already know how to do those, we just don't want to do it because all first world countries are capitalist and solving those problems isn't profitable. At least, not profitable in the short term.
If, on the other hand, you believe the current round of machine learning will accelerate expansions to its own abilities until eventually it is augmented enough that it can iterate improvements in output faster than we can then a lot of those things you list don't seem unreasonable. After all, there is a canyon of a difference between "having an answer" and "having a solution". Saying "get rid of your AC, stop taking vacation, only go places you can walk or bike, don't eat the food you like" and so on is an answer to climate change..." and so on provides an answer but one only a select few will ever take as it's an unattractive answer. What, though, if clean energy were 5x cheaper to make, 5x cheaper to store, and we found that 5x faster than we were expecting to? Suddenly you have solutions you couldn't have normally hoped for on things like climate change, not just answers nobody has been interested in. Types of solutions that make profitable sense (e.g. why spend money burning all of this non-renewable fuel to get the same energy at so much more cost?) instead of just moral sense. Types of answers that allow people to do more instead of less and still not have the downsides.
Of course... you have to really believe that first bit is going to get us there. If you don't (e.g. I don't think the current models will really get us in that loop directly, though they'll continue to be extremely good tools to leverage for certain use cases) then sure, it seems like bupkis to talk about those things. Even if you do believe the first bit... you also have to believe it won't be the end of us for some reason or another too and it's a bit of a thin line to sit on between those two views.
Closer than ever to what ? None of these problems could be solved by an llm, all of these problems take roots in the same soil as llms
- 200 years ago man made climate change didn't exist, our boundless quest for tech materialised it at break neck speed
- 80% to 90% of cancers have environmental causes, aka pollution/diet/&c. aka things we brought upon ourselves in our quest for tech
- Global hunger is a solved problem, we waste 1/3rd of our food production, the west eats 30-100% too many calories in the first place, we could easily feed everyone if we cared just a little bit