Google can shut your account for no reason and with no warning.

Pricing plans and other terms of service can (and will) abruptly change.

There is no guarantee that Google will even exist 20 years from now.

If we are talking about data that is to be handed down for generations, I certainly wouldn't trust Google as a solution. I do agree though that setting up self-hosted local/offsite backup, the kind described in the article, is out of reach for most users. Maybe redundant copies on every cloud storage provider will do the trick?