Do you have any good sources on the existance of the latter group? Also that could be seen as a subset of the former, I'd say people wanting fewer children have a combination of reasons for that, possibly including financial.
Considering Western countries are having to jack up immigration rates to make up the shortfall in reproduction, arguably contributing to a noteworthy increase in populism and racism (which does seem to greatly bother politicians and reporters), it seems odd that no one is interested in looking into the actual reasons for low birth rates.