If even industrial, mining, farming and generator districts provide housing for more people than they provide jobs (due to housing reduction), there will just be now way to take advantage of all the housing after some point. You hve a planet on which X amount of pops could live, but no jobs for them and absolutely no way to provide these jobs.
Why would you want to fill a planet to max housing and cripple your pop growth?
Population growth is a factor of current population and planetary capacity. Planetary capacity is a factor of not-built districts (4 per unused district on most planets) and excess housing. Pop growth will always be a full base 3 growth a month (before modifiers) as long as capacity is double your pops, but can grow to 4.5 a month if capacity is sufficiently high. For most empires, this means that resource districts reduce planetary capacity (districts provide 2 housing as opposed to the unbuilt 4 default capacity), and that you need to invest in city districts to compensate.
What this means is that Aquatics on aquatic worlds are going to have generally higher pop-growth rates on equivalent resource worlds due to a higher planetary capacity, and need to invest less in housing for the purpose of planetary capacity, saving minerals and energy/admin upkeep. It's not like aquatic are getting
fewer jobs per planet, they're getting more growth to fill the jobs they do have sooner, and then having more growth-capacity left over.
Whether the pop has a job on that specific planet awaiting them is irrelevant, because pops will either auto-migrate or can be moved for a trivial cost to an available planet. It's the pop growth that matters, not stacking a planet to have jobs = max planet capacity.