Likely, those customers who in the past have foresworn pdfs in favor of a print-only mentality might need to adjust their thinking if they wish to have the kind of varety to which they are accustomed.
Speaking for myself only, that will
never happen. I
hate PDFs- all of them, not just the ones for RPGs. I haven't even opened the ones I received as gifts or prizes (sorry, the Le).
For anything I'm holding onto long-term, I'd rather own something as hardcopy than as a collection of bits & bytes- books are computer/code upgrade-proof. As long as I can read, my books will never become obsolete due to a tech change.
The familiar reply is "But you can print PDFs!" Yes, I know that. However, that shifts the costs of printing from the publisher with economies of scale to me, the consumer, who has no such economies. Thank you, but no. There is a huge difference in cost & quality between a professionally printed hard or softcover book and a bound copy of a PDF I'd get at Kinko's.
Anybody who wants me (and some others, I'm sure) to buy their product had best continue to make hard copies.
To continue with prognostication, I'd even go so far as to say that if there ever comes a time when D&D becomes purely digital, that is the day I wouldn't upgrade. I'd stick with the last hard copy version available.