Is Adobe Dumping Web Browser development altogether, or is there something new on the horizon?

Adobe tried several attempts to become a true player in the web, but various misteps and general lack of trust by the community left those efforts dead. At this point, Adobe had effective thrown in the towel.

I wouldn't really consider Xd as part of the web dev market. But there's a lot of competition in the field. Electron and browser based tools are currently dominating (VSCode, and Figma), as opposed to the harder to develop native apps. Adobe was hoping to get a shortcut in on the action with Figma, which failed. Express is the closest thing, but it's quite simplistic. Express and AI seem to be the current focus. I personally don't see them trying a new fully fledged web design / development tool after failing to meaningfully enter the web dev market so many times.