Video games are generally upheld as an example of good self regulation. In the US the ESRB review system was created entirely by the industry. It has universal adoption and is enforced by almost every retailer (despite being a diverse group). Futhermore the ESRB has much clearer standards than the equivalent for films.

Is it impossible to imagine the industry creating a similar system around online transactions or gambling?

Maximising profits is literally the entire goal of corporations. Why would that be surprising?

Goes deeper. Self-regulation is sold by hyper liberals and libertarians as the pinnacle of freedom in capitalism. From individuals to corporation, where any form of regulation or control should be excluded

Self-regulation lasts for half a generation, at most. Then people take over who wonder why they are doing the regulating in the first place and/or see how to game it for profit. I think it does work, just not for long enough to matter.