My skepticism is mainly that this would be quicker than normal human iteration, or that this would substantially improve upon the strategy of simply buying more hardware. However, as we see in the recent case of eg. roBERTa, there are a few insights which substantially improve upon a single AI system. I just remain skeptical that a single human-level AI system would produce these insights faster than a regular human team of experts.

In other words, my opinion of recursive self improvement in this narrow case is that it isn't a fundamentally different strategy from human oversight and iteration. It can be used to automate some parts of the process, but I don't think that foom is necessarily implied in any strong sense.