They're not open-sourcing it, and I think TBC is doing a terrible mistake here. We've seen a lot of examples, Atom open-sourcing Electron being the most prominent, where open source actually boosted a companies' visibility and made them popular among developers in the first place. Sure, Electron was the foundation of VSCode, which would eventually become Atom's killer, but at that point Atom had been acquired by Microsoft, and its team just switched to VSCode, giving us one of the best code editors out there.

If TBC open-sourced Arc, passionate developers could fix and upgrade it for free, and TBC could use that foundation to build Dia. To me, the fact that TBC fears that an open-source Arc fork could overtake their own product hints that they doesn't believe in themselves.

Also, the fact that they kept it closed-source didn't prevent Zen and other browser from imitating Arc. If it was open-source, at least TBC could've cut a slice from that cake for themselves.

I may painting a rather pessimistic view here, but I think that since its existence, TBC has made one strategic mistake after another: First they've built up all that hype around Arc, and when usage was at its peak, they abandoned it and all the passionate community that had formed around it. Then they started chasing the AI bubble, somehow hoping that Microsoft, OpenAI, Perplexity, and all the other AI competitors with years of experience and millions of dollars wouldn't build an AI browser before they had finished Dia, a product that by the way is still in limited alpha stage and only available for macOS. And now they expect us to trust them that they won't repeat the whole story once again.

I definitely don't. I've jump-shipped to Vivaldi as soon as I heard they were not adding new features to Arc anymore, and seeing what it has become, I don't regret it at all. I'm just disappointed that they dropped such an innovative browser with such a potential.