I believe one of the main reasons is AI progress.
Who is going to pay for a web builder when you can easily ask a current LLM to build it for you? Not to mention what will happen when Agentic AI arrives and software development becomes somehow autonomous.
By open sourcing you can regroup, continue developing as a community effort, take advantage of collective intelligence, and try to figure out what to do next.
The new nocode is asking a bot to build it for you. Open sourcing is probably a last effort to try and stay ahead of the curve for as long as possible. There are way too many commercial nocode tools out there. Soon enough there will be a lot of open source nocode tools. Then…singularity? 