It surely doesn't help that SVG 2.0 is on a seemingly perpetual horizon for almost a decade now and nobody was willing to guarantee functionality everywhere. An

It surely doesn't help that SVG 2.0 is on a seemingly perpetual horizon for almost a decade now and nobody was willing to guarantee functionality everywhere. And SMIL certainly will not be in that one. Animation being only the tip of the issues, the moment you rely on anything, that isn't a filled polygon with no stroke, SVG support and compability starts falling apart in the most unexpected places.