I want production quality toolchain and runtimes. That's hard. Go has a high quality library of cryptographic functions. Hard. Go has a fast usermode thread scheduler with preemption on many platforms. Hard. Go has an incredibly low latency GC that doesn't need much tuning for most workloads. Very hard. Some of those hard solutions are self-inflicted by the choices made in the language, but the fact that they are solved so well is what makes it valuable. A mediocre implementation of Go would have less value. A mediocre implementation of a random language with a tiny ecosystem by comparison would be even harder of a sell.
I am by no means trying to say that Nim is low quality or not interesting for anyone. In fact, I actually think Nim is cool. It is not the only other smaller programming language I like. I have a strong affection for Zig as well. There are unique properties that make these languages desirable. Zig comptime is really cool for example. I like stuff like this.
But: I also think Go is a great piece of production-quality software. I know many people hate the language now, especially now that the honeymoon has thoroughly ended. But I still like it. I feel highly productive in it, the ecosystem is good, and at the end of the day, I know I can make reliable and fast software in it.
Corporate control is a shame, but the truth is that corporate control is not the problem at all. The problem is funding. Because anyone can fork Go, but can you pay maintainers? Can you run the CI, the website and playground, host the CDN with the downloads? Etc. Sometimes the answer is yes, especially with how much GitHub subsidizes a lot of those things, but in general the answer is no.
"Corporate control" is not the problem itself. Governance is just an outwardly visible consequence. The true control comes from maintainership and stewardship. Because if nobody is stepping up to the plate to take that role, then whoever is doing it today effectively has control over the project.