From reading the spec, the problem with SVG is that it is very difficult to implement completely due to the all-encompassing rendering model, javascript integration and animation scripting. This makes it difficult to read and write, without pulling in half a browser, and next to impossible to edit fully, unless using a text editor.

So if we do see more adoptions, it's quite likely they'll either end up incompatible with each other or some consensus on a work-able subset of SVG is reached.

Perhaps if W3C had done a reference implementation much like, say, H.264 has reference implementations, some of this could have been avoided?

I'd enjoy reading opposing views on this, interesting topic.