Interesting analysis of copyright effect on book investment.
TL;DR:
These results suggest that, at least for older, culturally valuable works with low fixed and marginal costs of production and distribution, underinvestment may flow from the existence of copyright rights, rather than from their absence.
Copyright is a crutch not only for the people for businesses too.
That’s quite interesting - even if their agenda is against libre culture they can’t help but admit that public domain does have business benefits.