Earlier quoted context omitted.
A lot of people are assuming the worst intentions here but anyone who has worked in an enterprise knows sometimes it's useful to build tools for your use and not to share. The tool might not even be allowed, C# is probably not in the supported platforms and even if it was, getting it into the official repos can be arduous. If OP really cared about maximizing everyone's productivity of course they would share the tool…
The question I have is how did incentives get so misaligned that this person feels that doubling the productivity of all their peers is unlikely to be worth the effort of presenting a tool.
Is it a percentage of the money saved? Absolutely not.
Is it a raise? Unlikely.
Is it a pat on the back? Maybe.
Is it more work, and a lot of pain supporting the tool in ways it was never meant to be used? Absolutely.
And it'll also mean a larger workload and more stress now that the company knows how much easier the job is now.
With that outlook, why would they share it? It makes their life better and easier as it is, and releasing the tool is all or mostly negative.