Since Google Cast has been open-sourced (upstreamed to Chromium), does this make it the de-facto alternative to Miracast? My Roku supports screen mirroring, but

Since Google Cast has been open-sourced (upstreamed to Chromium), does this make it the de-facto alternative to Miracast? My Roku supports screen mirroring, but the fact that apps and companies are more keen on supporting ChromeCast has been frustrating.