The flash plugin was always just an output format for Adobe Flash, which is now Adobe Animate, and the reason Adobe can kill the plugin is because it's simply not necessary anymore: as of many years ago (since around when the iphone came out and didn't support the flash plugin) it has been possible to make the exact same stuff in the current version of what's essentially the same program and export it as standards compliant html.
In other words, Adobe isn't killing flash (which is now Animate) at all, they're just killing an obsolete browser plugin format.
If this type of animation is less popular now that's just an issue of fashion; if people still wanted to make the exact same type of animated landing pages using Adobe Animate they absolutely could.