The orbital and surface populations are now separate so it doesn't really make sense for them to influence each others growth, especially as each is subject to different constraints. In pure mechanics terms, having the orbital population separate actually increases the planetary growth because smaller populations grow faster.
It increases % of pop being grown slightly, but you do so by reducing total number of pop growing, which doesn't increase the final amount, instead lowers it.
Also, given that all people are commuting to work on the world unless you have a shipyard there, makes sense you wouldn't see strict population control on habitat anyone can choose to leave at any time to move to surface and leave a free space for someone with no children to move into.
At least not neutering pop in them would go a long way to make them useful in regular games instead of heavy RP ones.