Not sure how this information is useful: the mom-and-pop businesses like the pizza place and copy shop look like they're deliberately understating their profit (perhaps to avoid the IRS?), and the finance types make a lot of money.
You're right it's not new but I find it interesting to see how other industries make their money. For example I didn't realise that MOMA made such a huge loss on ticket prices or that yoga places make minimal profit.
It's also useful to think of how business works in various fields in the physical world: you can find real opportunities for web startups or software to fill a need.
E.g. the real estate industry is huge and agents in particular earn large commissions = opportunity for Zillow, Trulia.
It's neither new nor interesting.