Realistically speaking it's also much harder to achieve the same level of impact back then as most, not just low-hanging, fruits have been plucked.
Won't this always be the case?
I mean, if you look back 50 years, they look like low-hanging fruits, but at the time, they weren't, only with the benefit of hindsight do they look like low-hanging fruits.
Similarly people in 50 years will say we had all the low-hanging fruits available today in subject/area/topic X, although we don't see them, as we don't have hindsight yet.
Like, these things seem obvious in hindsight even now.
You already have the whole Internet of data. You already have GPUs. All you need to do is just use the GPUs to feed the scraped (and maybe not-so-legally downloaded) data into some artificial neural network and you'll get a rather intelligent AI! How could one possibly think otherwise?
They look low hanging fruits when you have risen above them.
Very often, the thing that seemed impossible that suddenly wasn't anymore looks "obvious" when looking back at the completed solution.