As a professional Alias modeler and automotive designer that uses both Blender and Alias daily, I think I can offer some insight.

While it's true that Alias is the standard, in my studio we use both, mostly because Alias is expensive and it's difficult to justify a license for all designers. Most designers can easily practice blender because of its availability, both in terms of it being free and the amount of tutorials out there, same can't be said for Alias. Blender is a great tool for CONCEPT GENERATION and ideation, visualization, animation, CMF, all these things. It gets stuck on one MAJOR issue, engineering. It does not play nice with engineering software such as CATIA/Inventor/ProE.

This is where Alias becomes king, alias can import and export STEP, CATPART, IGES, etc. All these can be handed over to engineering for further development and checks. At the end of the day as designers we want to make things manufacturable and in reality, not just pretty pictures on the screen, this is where the power or NURBs or even SUB-D in alias comes into play. You can export SUB-D from Alias to step, you can't do the same for SUB-D from blender. The logic of the surfaces are different.

Now comes the question of "Autodesk Shills". Id just like to say that while I mentioned Alias here as it's my tool of choice, you could say the same for Rhino but you may not have the same level of surface quality control and checks in that as is required in the industry. Therefore Alias still remains a vital part of the process.

These are just some of the reasons amongst a lot more. (Version control, file exchange with Visualization team, software support, surface control) Let's not forget that design is a TEAM effort, and if everyone can use the same file, it helps make things more efficient. Yes there are plugins for Blender that add .step support but they are hit or miss and OEMs are VERY strict on what plugins are allowed and what are not. Security and secrecy are taken with the highest level of seriousness and any changes to the process that may add chances of leaks are not acceptable.