I doubt they have thousands left given many retailers have been asking for them and being told no, but I know that certain distributors keep books in their van/inventory which don't show up in a warehouse and are not assigned to a store. That happened to me with the 100X the Cash. Near the end of the game when there were almost no confirmed books anywhere (warehouse, District Offices and vendors), I got a call from AK's telling me that their distributor found 10 books in her van and was going to distribute them. AK's got them because they knew they could sell them.
I am sure there are not thousand of books left for SM, but the true population is probably about 100.
I don't often go on rants, but this issue brings me to an important point the vendors lists do not include every location with the books.
Several years ago, I made serious effort to find the last top prize in the old $3M Monopoly, the old $5000k a week for life (not the current one) and the 100X.
As I mentioned above, AK's ended up with 10 books of 100X despite the game not being available anywhere. Like we do now, I ordered lists of books at vendors throughout the state every month. None of the vendors had anymore of the 100X. I bought the 10 from AK's and got about 2/3rds of my money back. Later on, I looked at the list of winners on the FL's lotto's website and I found that a $1M prize was claimed by a guy in St. Petersburg at a 7-11. That 7-11 never showed up on the list of vendors selling the game at any time for over a year and boom...it sells a $1M prize.
On the $3M Monopoly, the statewide list of vendors only had about 25 places and I contacted each of them. Just as I was about to make the trip to buy some, a guy in Defuniak Springs hit the last top prize. That vendor location never showed up on any of the vendor lists.
On the $5,000 a week for life, there were a few hundred places across the state with the tickets in their inventory (according to the reports). I was buying up the tickets in Jacksonville and some in Gainesville when I visited friends. All of a sudden, a woman in Gainesville hits the last top prize. That vendor location did not show up on the vendor list either.
Now I know some of the top prize locations have shown up on the vendor lists. But it is a word of caution. My experience is that after all of this, someone in Pensacola can end up buying the last top prize in the SM game at a location that never showed up on a vendor list. The vendor list is helpful to find locations that sell certain games, but those games may also appear at locations not on a vendor list.
End rant...