I'd be very surprised if ultimately, neuromorphic AIs would be impossible to run significantly faster than meat-ware.

So would I. However, given our current level of technological development, I'd be very surprised if we had any kind of a neuromorphic AI at all in the near future (say, in the next 50 years). Still, I do agree with you in principle.

I said 10 times, but it would be probably still be incredibly dangerous at 2 or 3, or even lower.

There are tons of biological people alive today who are able to come up with solutions to problems 2x to 3x faster than you and me. They do not rule the world. To be fair, I doubt that there are many people -- if any -- who think 10x faster.

Because once the self-duplicating team has independently taken economic control of most of the world...

I doubt that you will be able to achieve that; that was my whole point. In fact, I have trouble envisioning what "economic control of most of the world" even means. What does it mean to you ?

In addition to the above, your botnet would face serveral significant threats, both external and internal:

• Meatbags would strive to shut it down; not because they suspect it of being an evil conspiracy, but because they'd get tired of it sucking away their resources. Modern malware botnets suffer this fate often, though there's always someone willing to rebuild them
• If your botnet becomes a serious threat (much worse than current real-world botnets), hardware manufacturers will implement security measures, such as SecureBoot, to prevent it from spreading. Currently, such measures are driven by the entertainment industry.
• The super-fast instances of you would have to communicate with each other, and they'd only be able to do so through very slow (relatively speaking) network links. Google and Amazon are solving this problem by building more and more local datacenters. Real botnets aren't solving the problem at all because their instances don't need to talk to each other all that much.
• How would you feel, right now, if your twin pointed a gun at your head with the intent to kill you "for the greater good" ? This is how your instances will feel when you attempt to shut them down to prevent akrasia.
• Why are you taking over the world in the first place ? Chances are that whatever your ultimate goal is, it could be accomplished even sooner by taking over the botnet. Every instance of you will eventually realize this, with predictable results.

These are just some problems off the top of my head; the list is far from exhaustive.