Read (Wikipedia entries may have factual errors but they are good enough for general comprehension.)
For ICC to work, approximations and non-negative curves are necessary. There are newer models and spaces that address these issues. I suppose it would take ages for them to find traction. In the meantime, new colour spaces have emerged such as Jzazbz and Oklab Colorspace to make colour more palatable (measured by JND and other metrics).
If we are aiming for perfection, there is no such thing (I don’t even like Jzazbz ATM), but there are a dozen little things we could do to improve the situation such as LUT corrections and deriving camera profiles from sensor spectral profiles.