are you kidding? he totally made the place better. did his job infinitely better than the job description required and what did he get for all his trouble? a big slap in the face from his boss. of course he left and took his skills with him. most companies just don't know how to recognize and appreciate above average skills/productivity, this is sadly a recurrent feature of many work places.
Just once I would like to read one of these stories where the conclusion is "and the company rewarded me with a large bonus and a paid two weeks of leave, and when I came back they had lined up some training and a project plan for me to stabilise what I had built and automate as much of the drudgery as possible"
I tried to force this at a company I was at. I was like a robot, automating as much as possible, anything and everything I touched. Spreadsheets, data loading, surveys, analytics, daily reports. I even built a chrome extension to improve a cash transfer approval workflow.
Weirdly enough, the director that forced me out had been a programmer in a past life. All he could see of me was that I was a cost center on his spreadsheet. He never sat down with me to ask what I did all day. He'd see me in a corner of the office wired in and I guess he assumed I was watching cartoons or something.
Fuck 'em. I left and I'm sure dozens of systems I had built and maintained broke, just by virtue of my company email address being shut down. I did try my best to document what I could and onboard others. There's only so much you can do in two weeks when you have to start with explaining what Firebase and Google Apps Script is to multiple people.
Hopefully more like, after the program was stabilised and automated I leveraged my new skills and left for more money elsewhere and on good terms with my company.
How is that your conclusion? OP had a number of things that were improved in-scope of his role, specifically cited this was before offsite version control, and that his replacement somehow deleted things.