Ron Amadeo writing for WIRED
The only power RCS has comes from the fact that your carrier might do it, which would instantly upgrade the baseline messaging service it offers on (at least new) phones. RCS's power comes from it being the default. Google's version of RCS isn't the default, though. You need to download the Google Messages app to use it, and Google Messages isn't the default texting app on most phones. The app is not required to ship alongside the Play Store like Gmail, Google Maps, Search, and other top-tier Google apps, so most OEMs don't ship it at all. Instead, they opt for their own messaging app.
I don't have high hopes for RCS.