Embeddable fonts are CSS, which is orhogonal to HTML5. Shadows and gradients are in <canvas> 2D context, but the well-known ones are also CSS properties, not HTML5.
SVG is based on VML. Microsoft proposed it to W3C (http://www.w3.org/TR/NOTE-VML), and W3C developed it further until it became SVG.
Microsoft's shadows, gradients and opactiy were based on DirectX filters with own horrible syntax, that didn't even tokenize according to CSS syntax. It couldn't be accepted in original form. Current syntax has been mostly invented by Apple (but gradients have been deemed too ugly as well, and spec went with Mozilla's syntax).
Microsoft's APIs may have been first, but they're not pretty. PPK calls IE-derived drag'n'drop API a "fucking disaster": http://www.quirksmode.org/blog/archives/2009/09/the_html5_dr...
Sadly, lots of Microsoft's and Netscape's Browser War-era inventions are in HTML5 only because lots/high-profile websites rely on them.