The gradient mesh and drop shadow were exported as an embedded image by Illustrator, so it was never tried to do it via pure SVG. But I guess the author doesn'

The gradient mesh and drop shadow were exported as an embedded image by Illustrator, so it was never tried to do it via pure SVG. But I guess the author doesn't have much experience with SVG's feature set and instead just fiddled around with Illustrator, looking at the export results and drawing conclusions for SVG.