All of science is getting harder as the easiest discoveries are all pretty much behind us.
LLMs were a breakthrough I didn't expect and it's likely the last one we'll see in our lifetime.
famous last words before quantum physics hit
The additional irony here is that LLMs are a tool that is likely forever damned to regurgitate knowledge of the past, with the inability to derive new information.
Specific fields may not advance for decades at a time, but we are hardly in a scientific drought. There have been dramatic advances in countless fields over the last 20 years alone and there is no good reason to expect such advances to abruptly cease. Frankly this is far too pessimistic.