The majority of those patents are low quality and prior art laden. They were used to shake down Android OEM's that didn't want to go to court. Barnes & Noble called them on their extortion games and both companies immediately settled with Barnes & Noble also setting up a joint venture. Microsoft knows their junk and doesn't want to actually prove they aren't. Any court case involving an Android OEM will automatically get legal aid from Google in invalidating any patents presented.
According to an analysis by NCAM
21% of Microsoft’s alleged Android portfolio scored as
commercial versus 79% as non-commercial. This means
that only one fifth of the portfolio was directly
commercially relevant, casting doubt the overall
viability of the Microsoft licensing packages on offer.
There are a surprising amount of abandoned and expired
patents already in this space. Much of the Android
platform may, in fact, be a 'Freedom to Operate' space
and already part of the public domain. There may well
be alternatives to the Microsoft licensing packages
that could be assembled from the rich vein of patents
that occupy the 'Freedom to Operate' space.
>In sum, M-Cam's analysis suggests that Microsoft's claim to ownership of the Android OS may not be as strong as it has hitherto insisted it is and it asks:
The question remains as to whether Microsoft actually owns proprietary rights
to the Android OS or is the company unfairly taxing device makers by exploiting
an uninformed belief in its supposed innovation?
According to an analysis by NCAM
>In sum, M-Cam's analysis suggests that Microsoft's claim to ownership of the Android OS may not be as strong as it has hitherto insisted it is and it asks: http://www.i-programmer.info/news/193-android/7537-microsoft...http://www.m-cam.com/sites/www.m-cam.com/files/Patently%20Ob...
https://seekingalpha.com/article/3545506-microsoft-sacrifici...