https://arstechnica.com/gadgets/2023/05/google-will-start-deleting-inactive-accounts-after-two-years/

You may have thought a Google account was forever, but the company's latest blog post details a new policy of deleting inactive Google accounts. The new deadline is two years—if your account hasn't seen "activity" in that amount of time, Google is going to delete your data forever.

The company pitches this as a way to prevent spam. The blog post says that "abandoned accounts are at least 10x less likely than active accounts to have 2-step-verification set up," and once they get compromised, they become vectors for spam and identity theft. Deleting old accounts and freeing up storage is also probably a good way to cut costs, which has been a thing at Google lately.