Is profit margin not partly a function of competition? A retail business is easily replicated, hence retail businesses have minuscule profit margin. Insurance

Is profit margin not partly a function of competition? A retail business is easily replicated, hence retail businesses have minuscule profit margin. Insurance companies have lots of competition, also low profit margins. Making a top of the line smartphone does not have a lot of competition, hence higher profit margins. Medicine is patented and hence does not have a lot of competition, also higher profit margins.