Anyway, the point of all of this rambling is to ask: Why is it so challenging to provide proper Collada support?
The main issue is lack of an easy-to-use multi-platform COLLADA SDK to export/import compliant files.
Add lack of conformance testing, and complexity of the COLLADA standard. COLLADA has COLLADA DOM which is terribly difficult and error-prone to use, so many avoid it. This is very unfortunately, because it encourages proprietary standards, such as FBX. FBX has an easy to use SDK.
Except for Bullet, the tools you mention use non-conformant COLLADA exporter/importers. CreateDynamics, Scythe and Blender in particular. Blender uses a python script with very limited COLLADA support. So if you want your tools to be better COLLADA compliant, it is best to contact the tools providers.
Bullet and its Dynamica Maya plugin uses the COLLADA DOM to guarantee proper conformance. A future physics composer will also use COLLADA DOM.
Apart from that, we are working on a binary companion format, based on IFF, for in-game usage. There will be converters from COLLADA to binary IFF.
So I have no clue what was going on there, but my guess is that there was mistake in reading the Collada file. What's the point of going through the trouble to get Collada working with Bullet if I can't even load a simple convex shape?
The issue is almost certainly a tool export problem, not import.
If there is any issue with COLLADA physics support of Bullet or Maya Dynamica, please let us know and share the .dae file.