I think it will utterly fail. Some interesting spin-offs may still happen but the whole project is a great exercise in marketing, not so much in science.
I'm involved with HBP and other non-European and European national neuroscience projects (though I am neutral here, just a university-employed engineer), and the science in the recent phase (starting in April this year) is a complete break with preceding funding phase and on-par with other projects. The people leading the science subproject are actually leading PIs on the topics. For comparison, let's name Allen Institute, though Allen is more a monolith, whereas HBP is more like micro-services, with a high cost in coordination, but now a focus on "FAIR" aspects like open-ness and reusability.
The infrastructure side is also coming along, and will provide an AWS of neuroscience (6 national HPC sites, multi-zone OpenStack/OpenShift, 2 neuro-morphic platforms, neuro-robotics platform, federated IAM, metadata and object storage stack, dedicated clinical infrastructure, etc) , but the failure or success will depend a lot more on the larger community getting convinced to engage their workflows on the platform. If people collectively agree that it isn't worth using, then the infrastructure teams never get to justify the whole thing, and it will flop. In that sense, the marketing aspect is not a facade, but a necessary condition for HBP to become a EU RI.
Of course I have no chickens in the fight; if it flops I can keep writing my shitty works-on-my-computer codes for one off unreproducible research projects.
https://www.sciencedaily.com/releases/2009/09/090904071908.h...
To make that claim in 2009 was complete and utter bullshit, if you've sold your project on grandiose claims like that then I don't think you are into science.
Maybe my problem is that I don’t see myself as “believing” in the project or not: it’s easier to learn from failure in fact. If the whole thing fails, it will make the EU a little more cautious about the next potential flagship project. Which is presumably what all the FUD surrounding HBP is about.
The EU should have insisted on believable deliverables. At the time I was highly critical about the claim, it being 11 years ago doesn't really matter to me, it was obvious that you could not extrapolate from the state of the art+a relatively limited amount of time to such a game changing deliverable (essentially: general AI).
I sincerely hope that you will be able to come up with enough results worth applying somewhere in real-life projects and products that in the end it will all be worth it. Best of luck to you.