And, years ago, Barclays Bank advising people on starting in business, said that their experience was that every business in a street made the same sort of profit. That remains true. You get odd circumstances when one business does better; that was true of opticians, for example; but, in time, these blips disappear, as it did with opticians.
You should only be in a business, as with being in a job, because you love that business. You'll be working 24/7 to get it going, so you'd better!