I'll try not to do another wall of text since we're mostly in agreement, but I will make a couple final comments:
> Your argument about who it would or wouldn't be good for seems a bit contradictory and I struggled to follow it. You're arguing it would be both bad for Google and Microsoft yet also make them stronger.
What I meant is, if e.g. Page and Brin in 1998 had no access to government funding and research because it was privatized by e.g. AOL, there wouldn't be a Google today. But if we were to privatize all research, Google of today would certainly like that insofar as it strengthens their market position (jut like the AOL of 1998 would like the situation), but it also means they have to start funding more research because now they can't get any from the public.
> - The web was very briefly funded - What government funded tech was Microsoft built on? - Neural networks were a backwater
But the point is that it all started with government funding, so we need to be very careful about the consequences of privatizing it all. Today, ideas start out funded by the government, they gain legs in academia, move out into corporations, and are productized and disseminated to the public in the form of consumer goods. This is the progress pipeline, and it's proven extremely effective and enduring at driving innovation.
You want to cut out the beginning of the process because you think corporations can handle that part, but I don't think you've really demonstrated that. Can you point to any tech product out there that is exclusively built on in-house, private research? I certainly can't think of one.
For example, you bring up the origin of Page & Brin. Yes, they never finished their Ph.D., but the fact is they did meet in grad school while they were doing NSF funded work. Brin was at Stanford on an NSF fellowship. They built the first prototype of Google on an NSF grant. They were mentored by academics who also were funded by the NSF as professors and graduate students themselves. You take that funding away, and maybe these two people never meet, maybe they never learn what they need to get that spark of insight. So I agree with you that the next Google will come from the same place the previous one did - a government-funded research lab in Silicon Valley. The garage is where they moved their operation only after they had already used a lot of NSF money to get their start.
> 1. DARPA is military research and therefore structured differently to how the NSF does things. The very structure of it as a Grand Challenge is a clue here: the output of the programme was cars (not) going round a track, not papers and citations.
The processes of getting grants from NSF and DARPA are very similar, and in most cases the deliverable is a paper. The Grand Challenges are the exception of DARPA funding, not the rule.
> Military R&D is different, governments can fund that semi-effectively because they actually use the outputs.
Yes and no. DARPA would like to use the fruits of its funded research, but it funds projects on a very long timescale, so what it funds may or may not be used in the long term. Sometimes the research is not to strengthen the military per se, but to strengthen American interests though creating domestic tech sectors. e.g. I'm sure the military would like to use autonomous vehicles, but what's even better is for America to have its own domestic autonomous car sector that can produce those vehicles.
> most academic output is useless and has no impact.
You've tried to make the case that we should optimize toward useful research, and companies are better at identifying useful research because they have a profit motive, but I still think it's difficult to say today what research will be important 30-40 years down the line. DARPA recognizes that it's very hard to tell how useful research will be ahead of time, and that corporations don't like to engage in foundational research when there is no obvious short-term path to profit. This was the entire point of the Grand Challenge series, and it worked out well -- they wanted to bootstrap the autonomous car industry, so they paid researchers to get them rolling and now look where we are. If the government hadn't gotten involved, there probably wouldn't be an autonomous car sector in the US today.
There are plenty of cases in our history where some technology seemed useless initially turned out to be bigger than anyone could have imagined. We need to be careful not squelch those ideas too quickly because they don't return an immediate profit. Things like the Internet and neural networks come to mind. A lot of people, particularly large corporations, thought the Internet was a toy when it first was introduced. Neural networks seemed like a dead end and then found new life. But the fact is they started in academia. The Deepmind arcade paper and essentially the entire deep reinforcement learning field today is based on decades-old research funded by the UK government. What if that research was locked away in a UK corporation? Would Deepmind even exist? That research was a toy for 30 years, until it wasn't.
The whole point of DARPA and other government funding agencies is that they don't know what the winners are ahead of time, and I don't think corporations can know this either. (if they could, why didn't they do more to fund RL research 30 years ago?). Therefore we shouldn't try to optimize for obvious winners because we'll miss out on non-obvious winners, which bring the biggest upsides. This means we have to fund losers and research that ends up not being useful, and we should be okay with that, because things have turned out pretty well over all.
> 2. I'm not arguing for prosecution of researchers who end up with null results!
Sorry I thought you were with this:
We will therefore prosecute you for research fraud and failure to meet the terms of your contract.
I guess you mean failing to meet the terms of your contract and fraudulently representing that. But it still doesn't address the incentive to commit fraud because if you fail to meet your objectives, you're still not going to get published and therefore won't get the next grant, so your career is still derailed. It just means people will try to hide the fraud better.
After I typed all this I realized I failed at my pledge to not give you a wall of text. Oops!