This is not exactly true, at least according to the DOC FAQ[1]. Inmates can still purchase paper books, and they are "working on a process that would enable the DOC to accept free books for the general inmate population."
Even beyond that, all mail (excluding legal communications, e.g. from a lawyer) is scanned and delivered via tablet for free. So, just mail desired books. The USPS has a discount rate for books anyway.
This is a serious, and typical, omission on WP's part.
I am a Pennsylvanian (or rather, was, and my family still is) and we don't have some magical red phone to our various governing bodies. This is not just PA. This is broadly countrywide, an eroding of civil liberties, often with a disproportionate focus on the incarcerated, and a pivot of govt from serving a wider breadth of the electorate towards special interests. Recall the comparatively recent rollback of private prison legislation and how their stock bounced? It's very clear where the incentives and accountability lies for the govt. decisions we're seeing, and it's not in the hands of your average voter.
To not just have this be a cynical "there's nothing to do give up," take this as, "this is a much broader problem than PA, fight the good fight, get people angry/willing to go to bat even if it inconveniences them, don't allow the excuse of "they deserved it" (incarcerated), make your elected officials accountable (even if only through social pressures and stigmas), and spread the message." This is one tiny battle in a war that I worry we're losing ground in.
To clarify what was a very tongue in cheek statement with the assurance that I regularly petition DOC, governers, congresspeople and senators, I meant in the sense that I've never found those channels to be responsive or impactful in the way a "direct line" might be. I should perhaps have said, I don't think PA residents have any special powers in this respect, moreso than citizens of a nation might, this issue certainly seems more wide-reaching.
Anyway, don't let me take away from your very valid point. To those who aren't leveraging contacting your representatives, you probably should. I'm just not convinced it's sufficient, even minimally so.
1. https://www.cor.pa.gov/Initiatives/Pages/FAQ-New-Procedures....