Sorry if this should be elsewhere but the level of technical detail in the main pollard kangaroo method thread is far beyond my level of technical understanding.

I just want to check my understanding and see where I might not have a good grap of the basics before proceeding. My assumptions are below;

* The pollard kangaroo method can drastically reduce the amount of work required to obtain the private key from the public key but requires the public key as an input to do this.

* Once an address has spent some of it's funds that address public key is revealed in the spend transaction.

* The funds which are not spent are returned to a change address leaving a balance of 0.

* The address should not be reused as a malicious actor can start generating the private keys from the moment the spend transaction is confirmed.

Feel free to correct any of the above points but if the above is correct; can anyone answer the following;

* Address reuse was extremely common in the early days and there are several addresses with 1000+ BTC balances with outgoing transactions revealing the public key.

Why has this not been used to steal the funds?

I'm sure there is a limiting factor to this method but I could do with it being spelled out in layman's terms.

Cheers.