I need technology patent terms to last centuries, thousands of years even (not necessarily millions though). Obviously I don't need the Patent Laws to change overnight. The Laws can take its time to update.
What reasonable (at least to us in the present day) justifications could be given to change patent terms lasting from ~20 years to such incredibly long periods of time.
The exclusive right granted to a patentee in most countries is the right to prevent others, or at least to try to prevent others, from commercially making, using, selling, importing, or distributing a patented invention without permission - Wikipedia
I've been thinking along the lines of far-future advanced tech. People (and hence their families), corporations, even governments will want to keep 'control' of such devices to keep the excessive royalties flowing to certain individuals or groups. Supposedly people may possibly live longer; will they not want access to their royalties longer?
Would sufficiently advanced tech for space exploration/planet colonisation/increasing longevity etc be enough of a justification to change the Patent Laws? I'm thinking of Tech that once, discovered and developed into a working technology wouldn't have too many further developments, obviously they will get tweaks and updates, but the core technology is still the same. Something along the lines of the 'wheel'...FTL/wormhole travel/antigravity/inertial dampeners/anti-aging tech etc etc.
Obviously if there are Patent Laws, this is not an Utopian Future. War is bound to break out and governments, or whatever stands in their place, can change, dramatically. I think, trying to make a new claim for a Patent held under a previous Regime might make for some interesting story-telling. So I'm not too focussed on how to transition regime shifts at the moment. Just focused on how the Patent Terms would have been extended in the first place.
While this is far-future scenario, and therefore all opinion-based, can answers please be focused on believable shifts in law-making, taking into account how humans act around large amounts of money. As many of our worlds are based many centuries into the current future, I believe the question is on-topic about WorldBuilding...or at least LawBuilding.
note: I do not know a lot about Patent Law, so if I've missed something that already exists, please let me know!