@Ngineer In the past, I have had pretty good luck finding the cars on MBK or other large online retailers, when the cars are released. And there is always eBay, although nowadays that often means a "buy it now" with a markup above MSRP and outrageous shipping charge. But mixed in there are usually a few honest brokers. So, caveat emptor.
All I can say is that to date, EVERY Bluford car I have ever ordered or pre-ordered has been delivered. Bluford is making the cars you want and has them slated for delivery (per their webpage when I looked yesterday) before the end of this month. Given all the global shipping delays, would not surprise me if they are late, but I am inclined to believe that if Bluford says they are coming soon, they are.
Maybe the dealer forgot to order them until past the deadline for pre-orders. Maybe he put in an order with one of the distributors he uses and those folks did not reserve enough to fill all the pre-orders from the dozens or hundreds of hobby shops they service. Who knows? But there is no info to indicate that Bluford cancelled any pre-orders from their end.