OFOTD,
You are making some extremely biased generalizations against rycote and rycote like products.
There are many options to run stereo configurations in a rycote and they I would not call them:
"Absolutely (the) wrong product".
This company specializes in making products for extreme recording environments that professionals use worldwide.
You may trust an unbrella with your mics, but when a strong gust of wind comes and messes it up, then what do you do?
Personally, I'll put some condoms on my mics, stick them in a rycote and fly them just like that in a mist or light rain, more wind and rain, then comes exterior treatment. To be fair in the discussion, I never tried the duck....