Moreover, isn't this what's happening to most software, everywhere? Cases-in-point:
Compilers - when's the last time you actually paid for a programming language? I know for me: SAS C in the mid 1990's
Databases - any new solution would likely use a free DB.. and why not?
Digital audio workstations - "free" ones seem to come out monthly
Graphic editors - 2D and 3D alike - the free varieties are getting better every year
Developer IDEs - From console editors to full GUIs to online offerings; all free
Even the business model of "hoping to make server software so good that everyone wants it" fails when hosting services just grab it, re-package with their own branding and profit.