Sure, once they get to RSI, it could be explosive improvement.
But real RSI requires closing the loop every time for every improvement.
There are three result types for each upgrade
1) the AI makes an upgrade entirely independently and it is an actual improvement
2a/2b) the AI makes an upgrade entirely independently and it is neutral or degrades the system
3) the AI makes an improvement that must be overseen by a human.
It only takes one bad upgrade to start spoiling the whole batch, even if the other 999 are good type-1 AI-self-improvements.
Otherwise the AI improvements will be limited to an AI-driven plateau or AI-driven self-degradation, or limited to a pace related to human capabilities.
They have already improved it so 80% of the Type-1 upgrades made by the AI itself. Great! Getting 80% of the next 20% will still require human input and likely the same effort. And so forth.
Just because we've gotten 80% in 3 years, and to 96% in the next two years, etc., doesn't really predict when we get to the ACTUAL 100% AI upgrades needs for real RSI.
Just thinking aloud here, but it seems it'll go at a slowing asymptotic pace, then some breakthrough may cause a jump in self-capability, but when is entirely unpredictable on any linear or exponential scale. I wouldn't bet a lot of money on it happening on an investment time-scale, maybe just a little like buying a lottery ticket.