I mean, don't these makers like (zoo med, zilla, etc.) know what goes into a incubator. I mean, i feel making something homemade or out of scratch will be less reliable, wouldn't you say?

I have seen tons of videos and pictures of homemade incubators, from coolers to mini fridges, i just figured ones that are already made and have a controlled thermostate and head element would keep the eggs nice and ripe as oppose to something you made.