Apologies for directly contradicting you, but it's false that Google don't delete. Google do delete in a timely fashion (which is required by law in many places!), it's just that for technical reasons, it becomes unavailable or possibly also crypto erased* first.
On an aside, such a setup is also a layer of defense-in-depth protection against a certain, uncommon class of bugs.
I do work for Google, but don't, in any way, speak for the company. All of the above information can be found on the internet, eg. https://www.quora.com/Does-Google-really-delete-the-account-... about Google accounts themselves.