I think it would be interesting to understand why Servo seems to have moved so slow compared to Ladybird.

I suspect Ladybird’s success has a lot to do with Andreas himself.

I think because Servo was orginally focused at researching new techniques for designing a modern browser, not creating something for users to user. Parts of Servo made it into Firefox.

Servo was picked up from hibernation by Igalia about a year ago. They have made very good progress so far, also with a small team.

The choice of c++ for Ladybird looks a bit odd, even from code reuse point of view since Firefox, Chrome and obviously Servo can share Rust code (WebKit will likely not?).

I don't think sharing rust code with Firefox was a goal for serenityOS.

Actually Servo development has accelerated greatly since 2023: https://github.com/servo/servo/graphs/contributors

There is already a prototype of Servo browser in Qt: https://www.kdab.com/embedding-servo-in-qt/