Of course the number of scholars killed is large in absolute terms and relative to the size of the Chinese research ecosystem at the time, but it's also small relative to the number of researchers worldwide at the time and to the hundreds of thousands (millions?) of Chinese scientists researching all kinds of things now, which is the result of explosive growth primarily over the past few decades.

Chen-Ning Yang was technically not wrong with his 1998 prediction, since Tu Youyou got 1/3 of the 2015 Nobel in medicine, but it didn't really make sense for him to link this to continued development, since the delay between discovery and award means that most of the prizes from 1998–2018 were for work that was already done before he made his prediction.

Over the same time frame, tertiary school enrollment went from 6.3% to 53.4%, and my 20–40-year prediction is based on a guess of how long it will take for the work of all those freshly-minted scientists to enter the range of consideration for a Nobel.