this seems rather prescient:
If anyone at a browser development company is reading this, vector image formats are more in need of disruption than raster image formats, SVG is versatile but it's bulky, a more compact vector image format would be welcome, especially in the age of responsive design.
That said, some technology standards can stick around far beyond what they should. MP3 is a classic example, there are far better music formats than MP3 (you'd be hard pressed to find a worse one that's still supported), but because of the sheer volume of music in that format, the 'good enough' status, and the limited abilities of some of the hardware players to handle better formats, we're stuck with it. This isn't something we should seek to encourage, but it does happen.
SWF. It's more than just a vector image format, but it is far better than SVG in terms of both filesize and resources required to render. Too bad for the "Flash hater's stigma" and the direction Adobe took their player after the acquistion... although there are now a few other alternatives including Mozilla's Shumway.
Also, since Adobe removed the restrictions on creating programs to display Flash content a few years ago, there's nothing stopping others from writing a minimal, image-only SWF plugin.
Something along the lines of HVIF could be a good fit for the web (perhaps less limitations on image ratios): http://en.wikipedia.org/wiki/Haiku_Vector_Icon_Format
Your criticisms are based upon nothing.
The rudiments of the vector description is extremely concise. That it is XML is superficially irrelevant, and if you really think the text markers are so important, consider it a highly compressible binary format via GZIP. Ultimately it doesn't matter.
I've never seen any metric that holds SWF as being more efficient than real-world SVG.