The trouble with patents
Is that there seems to be no due diligence in exposing prior art.
Often companies license because it is cheaper than fighting.
Look at the guy who patented yellow beans, and then sued someone who had been importing them into the US for 20 years.
Often there is loads of prior art, but it is simply ignored by the big companies, who also tend to ignore patents belonging to smaller companies.
Dyson couldn't sell his ideas for a bagless vacuum cleaner, so he built a company to sell them, now all the companies who turned him down are selling Dyson ripoffs.
The patent is now so devalued as to be almost worthless unless you can afford a top lawyer.
I hope Barnes and Noble stuff MS.