Just for the record, I am not necessarily disagreeing with "let's replace SMS", but Google can do it via a value-added service, which is much less regulated in most countries. Heck, Google already had it with Hangouts, and in my personal opinion it was just plain better than with Messenger. It was technically inferior with Whatsapp having E2E, but some people do prefer having a portable archive of their messages stored and access (much to the chagrin of cryptographers). However, killing it, resurrecting its corpse, and doing it again - well, it will not fare as everyone outside of Google predicted. Ron Amadeo had written a great piece about this in Ars Technica in 2021 (A decade and a half of instability: The history of Google messaging apps https://arstechnica.com/gadgets/2021/08/a-decade-and-a-half-...)

Messing with what is supposed to be a carrier standard, as I already think what is happening, puts Google to (in my opinion) a legally unreasonable position in some countries, and I won't be shocked it it will be treated as a carrier with licenses et al. (or rather, lack of licenses, which is just plain bad for Google). I won't be surprised if it turned out that many Googlers already knew that this is a bad idea legal-wise, but the higher-ups have approved this shoehorning.