Theory: brute-force key search Let’s say I want to generate many private keys so I can generate one private key (and thus a public key) identical to the richest bitcoin address.

But I can’t do that because my computer power is not enough.

What about if I create many machines, like the mining machines, but instead of generating hashes, they would only generate private keys, Let’s call them “Keying machines”

So I have many of those Keying machines generating thousands of thousands of thousands of private keys per minute.

These machines will only stop if and only if they recreate the private key-public key of the richest bitcoin address : 385cR5DM96n1HvBDMzLHPYcw89fZAXULJP )

Is this idea actually possible?
Sure, it's possible. In fact, this is exactly what the Large Bitcoin Collider does - It has successfully located a few private keys, mostly from a puzzle transaction that seems to have been made to test its progress.

That said, it would still take you an unreasonably long amount of time - The Large Bitcoin Collider took 1 year and 3 months to search 8,000,000,000,000,000 keys (8000 trillion).

There are 2^256 possible keys. Even if you are able to search 1000 trillion keys per second, it would take you 2.7×10^44 × age of the universe to go through all the keys. It's simply not feasible.

As pointed out by G.Maxwell in the comments, the Large Bitcoin Collider should be not be interpreted as a viable, secure, or even reasonable approach to this problem. There have been concerns about its safety and accuract (reddit source).