I struggle with the argument that RSI doesn't already exist like you say, it's existed since before the term LLM (hey, one that can be defined!) was common parlance. Though the biggest use for those is not superintelligence, it's to serve you ads and get your kids addicted to TikTok.
It has technically existed for a long time (for longer than the name), but only on academical applications for extremely limited intelligences that could only create something like themselves. And that is still the only form that exists today.
It was never powerful enough to optimize ads distribution, and all the claims people are pushing around today are plain bullshit.
What matters isn't 95% of humans, it's 95% of actual professionals. Benchmarking an AI accountant against people with zero accounting experience is worse than worthless.
95% better at 95% of the population is already approaching ASI. One could even argue that AGI is 50% better than 50% of the population.
All that said, this over rotation on benchmarking misses something critical. What is general intelligence? We assume that humans have it and we assume it is captured by benchmarks on "intellectual tasks", but it is probably the case that general intelligence is based displayed by judgement on uncertain outcomes. Benchmarks by their very nature have certain outcomes, they have a wrong and right answer.
Test AIs on questions we don't have the answers to and there is no clear right answer, but there will be at some point in the future. What will the economy do? Which US senators will be be re-elected that polling correctly suggests will not be re-elected. Which US senators, currently not in office, will actually pass bills representing the wishes of their voting base? What published papers will be seen are groundbreaking in 5, 10 15 years? What approach to unifying physics should be taken?