They did: Google Talk/gChat, Hangouts, Allo, Duo, Wave (I think it did messaging, I don't really know). There's probably more I forgot.
Google Talk notably supported tons of mobile platforms and was XMPP based and had federation, before they started down their path of reinventing messaging over and over.
Sure they created a lot of apps but they never replicated THE key feature of iMessage which is seamless SMS fallback within the same app. You don't have to even think about "Oh this person doesn't use such and such app"
Allo came the closest but messages sent to phone numbers not on Allo were sent through some proxy number so the recipient ended up getting the message as from some random google phone number.
RCS is the closest Google has ever come to the effortlessness of iMessage in terms of having a single app you can message anyone with, and incidentally there are some benefits if the other person is using a compatible app but regardless the message will get through (and from your number) one way or another.
> Sure they created a lot of apps but they never replicated THE key feature of iMessage which is seamless SMS fallback within the same app. You don't have to even think about "Oh this person doesn't use such and such app"
To be fair, while Google certainly could have had a better strategy, replicating Apple's would probably have been a failure.
For several reasons, iMessage's success is very US-centric. SMS fall-back is really not an option in countries where unlimited SMS isn't the norm. Google should have tried harder to acquire Whatsapp, or at least grab another big fish in this space (like Viber).
RCS is going to benefit carriers more than Google, since they might claim back some of the IM traffic. Google realizes it can at least try to control the app (Messages) which will be deployed to most low and mid-range Android phones, that are running stock or close to stock Android.
