In fact, Lazard themselves are very aware that their numbers are not representative for nuclear (as indicated by the footnote) and they themselves are very bullish on nuclear.

https://www.youtube.com/watch?v=16HVh_Fx6LQ

“We do not, in this study, try to cost out new nuclear” (2:35)

“We think nuclear will be a big part of the future” (2:47)

“the costs of nuclear should go down “ (12:54)

“next five to 10 years the nuclear bar the one that's most likely to change the most in in terms of cost reduction” (14:06)