However, they still sue everyone they possibly can in order to still lock down their market. For a few years now, the barrier for hasn't been the patents but for the cost of standing up to them in court.
Theoretically this is illegal. In practice, it's hard to draw a sharp line between "plaintiff actually feels his patent should apply here" and "plaintiff doesn't honestly believe his patent applies, but is using the courts as an anticompetitive measure".
The US patent litigation process is a horrendously bloated system that favors lawyers and companies with deep pockets, and makes it possible for a sufficiently rich and motivated company to bankrupt an upstart competitor.
