What's the meaning of this?
These are organisations that rely on technology and complex processes and in which the risks if those technologies or processes were to fail are very high, so high in fact as to rule out any option to hone the system by trial and error.

Question

What's the meaning of this?
These are organisations that rely on technology and complex processes and in which the risks if those technologies or processes were to fail are very high, so high in fact as to rule out  any option to hone the system by trial and error.

Answer

It's kind of a confusing and poorly-written sentence, but I believe it's trying to say: testing different options for the technology the company uses isn't possible, since if something goes wrong very bad things might happen.