system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: when Adobe Flash ‘died’, why did it cause every Flash program to stop running?

I don’t really have much of an understanding of computer programming, but I thought that Flash was just another program that was installed on a computer to access content. I read a story about how it caused a Chinese railway to stop running which is just mind boggling, but for simpler things like games and other interactive content, why can’t you still access them?
gpt
Flash applications won't run anymore because Adobe time bombed Flash player so that it would not run after 12 January. Microsoft and Adobe distributed these updates over a long period of time, which meant they were installed on the majority of computers. So, on 12 January, Flash stopped working on most computers.

This approach was taken because Flash was never designed with security in mind and as a result was very, very insecure with no possibility of fixing it.

The decision to do this was made, and announced over three years ago. It has been announced over and over again so nobody should have been surprised when it stopped working. But of course some people don't take warnings seriously.