Since other folks clarified that the suit needs to be about patents that are claimed to be essential for implementing W3C specifications, it just remains to fill out point 1 and swap A and B in your point 4:
1. Entities A, B
4. B sues A on a related matter, for example they claim a patent on some essential W3C technology
As a result:
5. A sends B their new license terms for the assorted patents they hold, plus a request for prompt payment of fees or removal of product from distribution
6. B considers whether they can pass this cost on to their customers and still remain competitive with C..Z who still get A's patent claims royalty free.
"History is a tool used by politicians to justify their intentions." -- Ted Koppel