The point is that there's a serious opportunity cost. By prioritizing customer service (to some degree), airlines can't charge sell space to businesses moving cargo for a higher margin.
The coffee shop argument doesn't really work because you can't keep scaling it. At a certain point people want space for books. But given that there's a space shortage on international flights, there's probably room for airlines to make more money by charging for freight instead of taking your luggage.
Hedge funds are investment vehicles that have avoided being heavily-regulated because they only accept money from government-certified "accredited investors." Their investment strategies are secret and unconventional. Some of them deliver floods, while the average one doesn't do that well.
Hedge funds provide liquidity, which makes it easier to trade; and conduct arbitrage, so that prices are muscled into line before they get totally irrational. (The latter doesn't always work though.) Meanwhile, since they have fewer safety nets, hedge funds are more aggressive about monitoring their own risk. They're better than banks in that respect, which are much more heavily leveraged and which have a history of being supported by the government when they mess up. Hedge funds have never been bailed out by the government like banks have time and again.
Outright seizure gets headlines, but the government can harm your property through regulatory takings as well. So crazy zoning can make your property value decline, and it's not well-established practice to compensate you for your loss. See Richard Epstein's work on this.
The Supreme Court will decide this year on a potentially really important case, Koontz v. St. Johns River Water Management District. A landowner wanted to develop some property, but the local water protection agency denied the permit because he wouldn't pay for mitigation that was totally offsite. This stuff can be borderline extortion.
The coffee shop argument doesn't really work because you can't keep scaling it. At a certain point people want space for books. But given that there's a space shortage on international flights, there's probably room for airlines to make more money by charging for freight instead of taking your luggage.