I don't think these colours look washed out. They look sharp and bright to me, (mirasol on the right, colour e-ink on the left).
I just summarized what I read elsewhere. I have never seen one in real life.
It does look good in the comparison you linked. It is being backlit though, while the E-ink is not. Maybe the mentioned blandness is more of a problem when used fully passively.
It seemed to have been a good competitor regardless, and it's sad that it got mothballed.
The short of it seems to be that production runs of Mirasol panels had very high fault rates, which lead to delays and losses. Qualcomm ultimately decided to abandon it and to fully focus on the Snapdragon processors which were perfectly aligned with the booming IoT space at the time.
Mirasol was apparently very promising and ahead of its time, albeit immature. It was based on electro-mechanical mirror pixels rather than dye. The biggest technical downside seemed to have been that the colors were pretty washed out and bland.
EDIT: It actually did make it to market. There was even a smartwatch powered by Mirasol (the Toq). It was never implemented by the big e-Reader brands though.