No bounce. My reading of the article is that the problem is with accounts that are still valid, but inactive. If you send a lot of mail to such accounts, e-mail providers flag you as spammy, apparently.
...which is remarkable because the email providers are the ones who are keeping the accounts open.
All they need to do is internally maintain a list of dormant accounts (as defined by not connecting to read email in some period of time); send a series of warnings to those accounts; stop accepting email for those accounts; at some point, delete the accounts and let mail bounce. Document the policy and the timeline.
What am I leaving out? Oh, forwarding accounts. Let the user mark them as forwarding accounts and change the "dead" heuristic to spot when all mail sent by the account's rules is bouncing.
I suppose that might cut the statistical boasting a bit (12 billion active users!) but at this point nobody has any sympathy for marketing departments anyway.
Email providers track "engagement", not just overall account activity. Plenty of "marketing" messages are sent to still active account and just go undread. Enough of this will cause messages to be routed to the bulk/spam folder.
I doubt this explanation. I have personally seen spamhaus blacklist a newsletter that was subscribed to using double opt-in. What happened: the e-mails never bounced, the provider just closed down and - what a "coincidence" - the domain ended up being owned by someone who immediately used it as a "spam honeypot" for spamhaus.
It's apparently impossible to protect a sender against this by other means than detecting real user interaction. Alternatively, blacklist providers doing this could be ignored...
BTW the OP said "dead", not "inactive but still open"