Yeesh, out of all the choices available, I had to pick the worst example, eh? Feel free to substitute "Live Mesh" or "FolderShare". :-)

msn messenger -> live messenger.

hotmail.com -> Windows Live Mail -> hotmail -> outlook.com

You missed a few steps for messenger: Live Messenger -> skype -> lynq -> skype for business

well basically we talked about renames and live messenger actually was canceled for skype and not renamed. the other examples were just renames with/without a new ui.

Lync / Skype for Business?

Lync -> Skype for Biz -> Teams

It’s been renamed again? Word of this has not yet trickled down to my group.

I wish they’d put some of the renaming energy into improving the reliability of their Mac and iOS apps....

Previously "communicator" ;)

I would say the difference with those examples and Pay with Google (as well as Google's other rebrands) is that Live Mesh and FolderShare really weren't being used prior to rolling them into Live Drive/SkyDrive/OneDrive (whenever those got integrated, it's been years). The rebrand was intentional to try and get them to be used more by attaching them to a more successful brand, which happened to be the one for our online storage.

Google likes taking successful products and then rebranding them out of the blue for no real reason other than to seem "integrated". Things like splitting off messaging from Hangouts, which was already an amalgamation of features and other products like Google Talk and the old messaging app. Or like Google Pay, which is an amalgamation of a bunch of other successful products like Android Pay (which was itself an amalgamation of other products like Google Wallet and Google Checkout along with certain acquisitions). With Google, it just seems like they constantly have FOMO of being on the "hot new brand".