Having spent the last 3 years building complex visualisations with SVG, the biggest drawbacks I found are:

- Poor optimisation. Browsers have done a lot to speed up HTML + CSS rendering via the GPU, and you can you use WebGL to make canvas fast. SVG seems to have been neglected in comparison.

- No layout management. HTML + CSS isn't perfect in this regard, but you still get blocks + inline text, floats, absolute positioning, tables and flexbox (and soon, grids). In SVG, you get absolute positioning, and that's it. If you want to do any kind of complex layout, you have to calculate everything yourself in script.

I'm not sure the major browser vendors really care too much about SVG. Compare the huge advances made in other areas of the web platform with the years-long, incredibly unambitious SVG 2 specification process.

It's a real shame as as this presentation shows, you can do some incredible stuff with SVG. But it could be so much more if there was just a bit more effort invested.

https://github.com/facebook/yoga