The problem with profit margins is that they're often artificially low in order to fuel business expansion, which may not be necessary.

I actually managed restaurant business. Our labor cost target was 15%, and food cost 30%. Then operating expenses like electricity, water, rent... I'd estimate there's 20% of revenue left over. Was our profit margin then 20%? No, because we were constantly buying new stores and random things we don't need. For example, a 16,000 dollar automated flattop grill that barely works, when we already have a flattop.

I'm often dubious of the "capital" that businesses purchase. Point being, profit margins are not really a good measurement of much. I can burn money and have low profit margins, if I wanted.