Minority Report.
There is also the old saw about thieves thinking everybody is dishonest.
The BPHs think that just because *they* would jack prices through the roof, thereby destroying the value of the ecosystem, *everybody* must be that short-sighted.
People buy ebooks from Amazon because they offer a good value--the moment they cease to offer that value, they'll go elsewhere. And there will be no shortage of volunteers popping up to take their money.