Earlier quoted context omitted.
Many of the old games and movies still play back well with Ruffle installed ( https://ruffle.rs/ ). Newgrounds embeds it by default for old interactive flash media that they couldn't convert directly to video. It's not a perfect fit, but it works. The speed of Ruffle loading on a page is similar to that of Flash initializing, so you can arguably still make flash websites and animations to get the old look and feel if…
It's good that we have the runtime to run old Flash games. What we lost is an extremely easy environment for authoring/creating them. Nothing has come even close since Flash. Not just game, but any kind of interactions and animations on the web.
Can a person not run Flash authoring tools with an era-appropriate operating system in a VM or something?