Imagine creating your own game engine in 1994 and being told that, no, sorry, you can't use it, because someone else has been granted a monopoly in that arena until 2004.
There's also laws forcing companies to share their patents at reasonable fees (for whatever definition "reasonable" has). That's why Apple can't stop Samsung from making touch-screen smartphones and tablets - all Apple can do is demand Samsung pay Apple the $10 per sold device (covering some hundred or so patents).
No, your own investment is ruined, because someone else was granted a legal monopoly over your own creation. You didn't even copy them, but you both invented the same thing at the same time and thy were the "first to file".
Yes, simultaneous invention is a genuine problem.
If I recall correctly (someone correct me if I'm wrong), one of the rules for issuing patents is supposed to be that when faced with solving the same problem, if the requested patent is an obvious solution for that particular problem by someone with experience in that industry, then the patent isn't supposed to be issued.
Not only do we need the patent offices to actually reject 99.9% of applicants by applying the originally intended tests (review by experts in the field as genuinely novel discoveries), we need those same experts to agree on actually reasonable time periods. My above example is of course a worst-case exaggeration, but the point stands -20 years on software is rediculous.
I agree with everything you mention here, except the assumption that 20 years is too much. If patents are limited to genuinely original inventions, aren't just abstract ideas (so other people can use the same ideas, just different implementations), and companies are forced to license them out (in certain circumstances) at court-demanded reasonable fees... I still wouldn't know if 20 years is overdoing it or not. It'd have to be decided by experts who actually study it, guided by the government (ugh) who'd set guidelines to determine what the actual goals are (sharing of knowledge publicly, for example).
If the current system is doing far, far, far more harm than good, and isn't actually required, and isn't fulfilling it's original purpose, then why can't "complete abolishion" be a suggestion for a solution/alternative.
It is a possible solution (I wasn't the one suggesting that that's not an option, that was someone else's post).
As far as software goes, it's not even a bad option, considering that the United States Patent and Trademark Office didn't even want to issue patents for software (until they were forced to against their will).
The thing is, it is still fulfilling it's original purpose, but it's also being abused. The purpose of the patent system is to share knowledge publicly, so companies (and indirectly, the public) can mutually benefit. With the provision that the company that created 'shared knowledge' can still profit off of it exclusively for a reasonable duration of time. If the past 'reasonable duration' is no longer reasonable, then perhaps it should be looked at and revised.
If the patent system is removed, or made of too little benefit, then corporations will revert back to what they did in the past: Trade secrets. Innovation won't be shared by big businesses, it'd be kept secret. Employees who come up with ideas will be forced to sign contracts promising that they'll never release or share that knowledge with any future employer or the public.
I like patents better. They need to be fixed, definitely, as do copyrights, but the primary fix is just making the gatekeepers obey their own rules.
The bourdon of proof lies upon those who argue that these rediculous artificial monopolies on thought,
Yes, it is artificial. The monopoly is the point, actually, but it's a time-limited monopoly of a short duration.
If, in the present day, the duration needs to be shorter still, that's a reasonable thing to explore. Though, you may still want to differentiate between software and non-software patents - if someone invents a physical invention, it may actually take him 20 years to build a successful business around it before he loses the patent. I'm not going to throw out arbitrary numbers about what is a "reasonable" length of time, because I don't know the answer to that - but it is something that the government should actually have economists consider and study.
Also, it's not supposed to be monopolies on thought. It's supposed to be monopolies on original thought. That the original thinker can profit from that original thought for a limited time before it becomes the patent-equivalent of public domain.
Since it's not currently working the way it's supposed to, we should figure out why and fix it. We know why: The gatekeepers are doing a horrendously stupid job of it, which permits patent trolls to abuse the system. So we should at least give a reasonable attempt at fixing that bug, instead of recoding our system from scratch.