Royalty free? Well, pardon my French, but fuck them. They are not in a position to license anything, that would be admitting they had a case to begin with.
And that is precisely what these people are after by making the offer — if others in the industry are willing to take licenses under a patent, then the patent owner can brandish that fact as indirect evidence of the patent's supposed validity.
That kind of evidence wouldn't be dispositive by any means. At trial, though, litigation counsel will put in any evidence they can — especially "proxy" evidence that can readily be understood by non-technical people such as judges and jurors. (A classic example of such proxy evidence is, "They lied!")
(Patent attorney here, although I don't do that kind of work anymore.)
A patent owner would "lose" a patent only if someone were to successfully challenge the patent's validity or enforceability, either in court or in a USPTO proceeding. If the patent owner were to fail to defend against the challenge, then yeah, the court or USPTO might invalidate the patent.
Now to be sure, if a patent owner were to wait too long to assert a patent against an infringer, that could complicate the patent owner's efforts to get royalties or an injunction (a stop-use order) later on against that infringer, and possibly against other infringers.
And any infringer might try to use the patent owner's delay as proxy evidence that the patent owner didn't really believe that the patent was valid.
But failure to assert a patent, in and of itself, will normally have no bearing on a patent's validity or life.
Failing to sue someone is not cause for cancellation of registered marks. Neither in USA nor EU AFAIAA.
This is not legal advice; it is my personal opinion and makes no representation about any associate or employee that I might be linked with.
Not quite. Thermos, escalator, and cellophane became generic terms, free for anyone to use, because everyone started using them and the trademark owners didn't try to stop them. [0] That's why Xerox famously advertised that we should say that we made a Xerox copy of a document, not that we xeroxed it.
(Aspirin also became generic, and thus free for anyone to use, in the U.S., but that's because the trademark was seized from its German owner, Bayer AG, as part of reparations after World War I. [1] Aspirin is still a trademark of Bayer in most of the rest of the world.)
[0] https://www.inta.org/INTABulletin/Pages/ASPIRINBrandorAspiri...
[1] https://www.latimes.com/archives/la-xpm-1994-09-13-fi-38019-...
FTFY.