Huh, that sounds like another bug.
I have some play testing and noticed that it's already pretty hard to grow residential houses, because the simple houses just grow and consume all the apples. Wondering what approach is best to balance the housing tiers. Maybe not having the higher tiers consume what the lower tiers need, or having a reduced chance to spawn new houses if a given tier has too many. E.g. if you have 900 simple residents, and only 10 residential, then the chance to grow into residential should be much higher than adding more simple houses.
What currently happens is that you supply apples and construction material, which makes the simple houses grow until there are not enough apples anymore. If you don't oversupply the city with apples, it will never grow residential. The same applies to highrise, but on a more complicated level.
My favourite approach would have been to display supply levels similar to the energy supply, but unfortunately there's no API to display graphs.