This kind of argument draws on the idea of the perfect, completed text as was intended by the author-god of that textual world. This calls into question the place of archival materials in scholarship at all, if Peter Stanford is unsure about making unpublished 'completed texts' available, then it would follow that the use of manuscript drafts (especially of a work with a final published version) is entirely put of the question. Giving the shade of the author final control over what they intended to be published must also exclude volumes of letters and journals being published. And so on.
As an example of poor literary executors Stanford uses Max Brod, who is responsible for the crime of not destroying Kafka's manuscripts. This is perhaps a poor choice of example as Stanford does acknowledge that Brod's actions mean that we have texts that are "now regarded as classics of 20th-century literature". He finds, however, that preserving a literary heritage is secondary to the "thrill" of rooting through papers and the money to which this can lead.
The legal tangles aside, Stanford's article betrays interesting sentimental attachment to the idea of the perfect, published text intended by its author. The stability of this idea is is being constantly challenged by the use of draft material in scholarship. Whilst there certainly is money to be made in lost works and archives, these works are important to scholarship despite, or even because of, their unfinished nature.