I mean, Web Components already gives you a pretty similar experience: you can stick arbitrary properties on your custom elements and use shadow DOM to build int

I mean, Web Components already gives you a pretty similar experience: you can stick arbitrary properties on your custom elements and use shadow DOM to build internal documents that outside code can't inadvertently access. That and WASM is basically feature-equivalent to what ActiveX was trying to do, but actually engineered to be a standard rather than just proxying everything to COM/OLE.