The thing that stuck out to me was they stated in the listing they're going to continue adding to the collection until a buyer is found. That doesn't make any sense to me.
Yeah, strange, you're either collecting, or not, and selling it off, stopping.
Here he just seems to know no one will buy it - such million dollar 'whole collections' auctions popped up over the years now and again, and never sold, AFAIK, so he's just holding it for an off-chance to get rich...
But rich people don't spend their money like that, and they like their things nice, new, and sealed, if possible. Not brought in to a pawn shop because they're in dire need of money, or have no respect or care for these items.
Someone having that kind of money for that kind of thing must be a big collector and aficionado, and likely has already a lot of what he's probably selling, and knows his tastes and preferences, and will rather seek out and buy whatever he needs individually.
Not just generic 'top 250 iMDB' rated, or all Disney animated movies.
Just getting it for a library or a private rental store might be feasible, but, again, government locations are already stocked, and either way them, and such store owners, get them in bulk, cheaper.
He might be able to sell it for $300,000, but then again that wouldn't be worth it to him - I wouldn't sell mine for that, and it's probably half as big, and 4× as good and diverse, country-wise.
P.S.
I'm using 'he' everywhere abstractly, a possible interested collector of course may well be a 'her', I just don't like writing 'they'...