Ron Amadeo, in a piece for Ars headlined “After Ruining Android Messaging, Google Says iMessage Is Too Powerful”:
Even if Google could magically roll out RCS everywhere, it’s a poor standard to build a messaging platform on because it is dependent on a carrier phone bill. It’s anti-Internet and can’t natively work on webpages, PCs, smartwatches, and tablets, because those things don’t have SIM cards. The carriers designed RCS, so RCS puts your carrier bill at the center of your online identity, even when free identification methods like email exist and work on more devices. Google is just promoting carrier lock-in as a solution to Apple lock-in.
Despite Google’s complaining about iMessage, the company seems to have learned nothing from its years of messaging failure. Today, Google messaging is the worst and most fragmented it has ever been. As of press time, the company runs eight separate messaging platforms, none of which talk to each other: there is Google Messages/RCS, which is being promoted today, but there’s also Google Chat/Hangouts, Google Voice, Google Photos Messages, Google Pay Messages, Google Maps Business Messages, Google Stadia Messages, and Google Assistant Messaging. Those last couple of apps aren’t primarily messaging apps but have all ended up rolling their own siloed messaging platform because no dominant Google system exists for them to plug into.