My favorite examples both involve markets: (for the sake of convenience I'll talk about these two products as if they already exist and work. They don't.)
1. Althea (https://althea.org/) is incentivized mesh networking. Currently, mesh networking is an under-provisioned public good. It's a public good because how would you even pay for it? If you want to provide bandwidth to some mesh network you need to spin up your router and then form some sort of business arrangement with all the other routers in range. If you want to consume bandwidth from some mesh network you must first form a business relationship with every router you'll be using. With a protocol such as Althea all you have to do is start your router and set a price in $/byte . Your router broadcasts that price, and assuming the price is competitive packets will start to be forwarded and you'll start to receive payments.
With Althea all of these business relationships I described before are still formed! However, they exist in the form of standardized smart contracts which are cheap and quick to create. Like in all liquid markets, there's no negotiation over terms.
While incentivized mesh networking is theoretically possible without a blockchain, the transaction costs are so high that I'm not aware of any deployments. The blockchainless answer for reducing transaction costs seems to be: create some central entity which everyone signs up for. It collects information on who routed packets through who and collects and distributes payments accordingly.
The blockchain answer gives you:
- no intermediary who takes 20% just for matchmaking
- an easy way of paying other parties
- no need to sign up or register for anything. You're just communicating with your peers!
2. Filecoin is distributed file storage much like Amazon's S3. Currently, there are only a couple suppliers (Google, Amazon, Microsoft, etc) who store your files. They have some healthy competition and economies of scale which bring your price down but supply is still rather limited: mostly because there's no standardized "file storage contract". Also, they seem to enjoy premium pricing, even with all those economies of scale they manage to be most expensive options. Backblaze and some company called Wasabi are much cheaper for what appears to be the same service. Can you really trust them though? My data is important. I'll put it into S3 just to be sure.
The Filecoin network goes through some crazy steps to prove that providers are actually storing the files they claim to be storing and actually replicating them the number of times they claim to be replicating them. This lets you trust any supplier on the network and turns object storage into a commodity. Filecoin also has the same blockchain benefit of requiring little registration. Do you have a desktop computer with a 2 TB hard drive, even though you're only using a few hundred GB of it? Start the Filecoin daemon and wait, after some time passes you'll have money.
This 0-registration is a level of UX which blockchains cannot currently provide but in principle they could. However, it's something that would be very difficult for any central service to provide. And again, the file storage becomes a commodity without any intermediate market-maker taking x%. The blockchain acts as that market-maker.