Bad math? No math has been presented except for that in the meme. I said that it doesn't take into account expenses. I don't see what's so controversial about this. You even admit it in your statement "expense model is totally different", thus implying that expenses exist in both services and factories (don't know why you are even bringing up factories in the first place as this is off topic).

Service business have heaps of expenses. Hospitality is an obvious one. Regarding tutors, they need extra space for kids, tables, chairs, computers, etc. If they tutor on location they need to pay for transportation.