It is not reasonable to think that retailers like Costco, let alone Walmart and the rest, would be willing to send Vizio's bulletin to all of the customers who bought the TVs at their stores, even if it were possible. How many here have received that bulletin from the retailers where they bought their TVs? I haven't and don't expect to. The extent of the retailer portion of the initiative was likely the exchange of defective stock that has been widely reported here, which I give credit to Vizio for doing.
I (and others on this forum) know about the bulletin, because somebody (I believe iautotron) posted a link to Vizio's Twitter announcement of it. However, that tweet has long ago fallen off the bottom of their Twitter page, and I see no evidence of it on Vizio's Facebook page. Also, Vizio has only ~146,000 followers on its Facebook page and ~12,000 on its Twitter feed, and how is Vizio going to use other online media to magically find their customers? That's all silliness.
The other 99% of Vizio's customers are not aware of the bulletin. If their TVs fail within the (known to them) one-year express warranty period, they will get their TVs repaired like any other problem TV during that time. However, for the TVs that fail in the second year, it is only a proportion of customers who will be resourceful enough to discover that there was a warranty extension due to the defective chip assembly.
If Vizio would just do what they said they would do
and directly contact all registered customers (e.g., send them an email with the bulletin), then the customers would know they are covered in the second year. And Vizio could probably send that email using less man-hours of effort than we have expended debating it here.