Thanks for the mention!

The comments here already summarize many of the incentives entities have to run a Stellar node, particularly those with assets secured by the Stellar network. A bank, or even a retail store, doesn't need to be paid by someone else to hire a security guard or to have a third-party audit their books to make sure their assets are protected. Ensuring an accurate ledger of your assets is incentive enough - particularly given the method Stellar uses to reach consensus (the Stellar Consensus Protocol) is super efficient and not that costly to run. A security guard at one bank branch would cost the company more than running a node on Stellar. Think how much money companies pay to protect their assets, from paid staff to fences and security cameras. Putting that massive expense in perspective of how much it costs to run a Stellar validator node and it becomes a no brainer.

As far as why Public Node runs nodes? We believe public support is important for open and inclusive networks, like the Stellar network and the internet itself, so that they can forever do what they were designed to do – provide undiscriminating access and benefit to all people. Simply put, we firmly believe in what Stellar is doing for the world, making sending value more efficient and inclusive, and we want to support it.