This is not an economic matter; it is a social foundation. A library is a refuge; you can provide solace in that refuge, and a promise for a different and better kind of future. It is morally incumbent upon you to do so.
I propose that public terminals be accessible on a tiered basis. If a certain percentage of a public library’s served population falls beneath the poverty level or a similar metric, the number of public access terminals is commensurately increased.