Many people (me included) don't trust Google to stay with any business besides advertising. There's been too many times that they have ended services with not much time to get off.
That and countless horror stories about once your google account or service is banned for whatever reason detected by their bot, you have no way to appeal with their nonexistent customer support.
This is what always puzzled me about the Google-Alphabet strategy, specifically the idea of having all the assets under a single share ticker (GOOGL).
The more services you put under one banner, the more the stink of one disaster is going to linger, and hinder adoption of the successes.
To me, a far simpler proposition would be a new brand & share issuance for each new sub-company (eg. Waymo), with existing Alphabet shareholders getting pro-rata shares in the new company.
I’d bet on it being about the recognition that Google has been a pioneer and thought leader in the scalable systems/hosting space and they didn’t want to throw out the baby with the bathwater.
