If someone doesn’t floss regularly and they get a few feet in front of me and are talking I can smell them.
If someone hasn’t flossed in decades I can’t imagine the stench up close.
Yeah, I hear you ... but flossing doesn't do much for flushing bacteria out of any existing tooth cavities, while it probably does help the gums to be irrigated, which would flush out organic matter that's slipped between gum tissue and the roots of the teeth.
My basic thought is that people don't need to brush their teeth as much they need to "brush" (massage) their gums. A centuries old adage to "brush you teeth" should really be "brush your gums": massage your gums to flush out the gunk that would otherwise become a garbage dump. That's a dump where bacteria will thrive, multiply ... and deposit a foul smelling waste. Maybe tooth cavities stink some also, but I think halitosis comes primarily from the space between the gums and the teeth roots.
Oh my, what would the ADA say? Is toothpaste even necessary? What would Colgate say?!!