That is absolutely true, and probably equally true for any other web application that was wasn't maintained for 10-15 years. But this is article is talking abou

That is absolutely true, and probably equally true for any other web application that was wasn't maintained for 10-15 years. But this is article is talking about the ability to run older applications, not about safety concerns about doing so. I just wanted to point out that, while Rails is far from perfect, from a software-archeological perspective there's not really much ground to pick on it. The ruby gem ecosystem (again not perfect) is at least pretty stable in the sense that 10+ year old libraries are readily accessible (as they should be!).