It's so modular that it's very easy to extend.
A new fluid sim algorithm? A few months later Blender is shipping it.
That's also the reason it's fast. It starts in one or two seconds.
But if you take into account how the Blender project is handled with consideration of how to sustain itself via the Blender Foundation, and all the related projects, you can observe how an outlier it is compared to all similar ambitious projects that are not doing so well.
This is a bad and a good sign: it makes evident how little FOSS projects take in account it's sustainability over time, on the other hand it presents an opportunity for huge improvements in this area.
My hunch is Professionals as users might also be a benefit as they will tend to put up with bigger learning curves if they see benefits in the end. Also professionals don't tend to care as much about look of the UI (harder to do without dedicated design resources) vs efficiency of using it.
That's like saying Linux doesn't have a great track record cause it hasn't replaced MS Windows. To be successful, they don't have to replace, just service a different niche / enable new or additional uses (e.g. I don't have $$$, I need better support&customization)
Gimp was used for a few movies https://en.wikipedia.org/wiki/CinePaint
A few successful examples of usage of X (like Gimp) in the industry doesn't make it remotely in the same league as proprietary star Y (like Photoshop). Don't try to create a reality out of the thing we all wish were true. FOSS is not winning those battles yet.
- the problem blender is solving is super hard
- the competition was way ahead
- FOSS don't have great track record for this kind of challenge (gimp has never replaced photoshop nor LibreOffice MSO)
- they don't have that much resources
- professionals are very demanding
- the graphic space is not really foss friendly
- the amount of work they poured into this is incredible
They are heroes really.