Because advocating for more nuclear power would not really help their goals now. 1) Every GW of installed renewable power makes nuclear plants less useful (and

Because advocating for more nuclear power would not really help their goals now. 1) Every GW of installed renewable power makes nuclear plants less useful (and renewables will continue to be built because they're too cheap to stop). People like to crow about "nuclear provides the baseload we need", but this is ill-informed nonsense; "providing baseload" is a privilege you get to enjoy if you are the source with the lowest marginal cost (which is absolutely not a given for nuclear power), and sure, you can operate a reactor in load-following mode by turning it off half the time but then the already bad economics become even worse. What you actually need is dispatchable power (thats cheap to install per GW, like gas) and/or more storage or better grid connectivity. 2) There is a lot of pushback from the population at large (especially in countries were regulators and operators are more corrupt/less trusted), building out nuclear plants is much more time consuming and expensive and the resistance against new sites is immense. Alienating half your support base by suddenly championing nuclear power for basically no reason is also a no-go.