Rails is an open source sourftware with hundreds if not thousands of contributors, its at version 7 now, if you think it's been "written by a product guy" you don't know what you're saying.
Modern Rails has been adapted to modern standards and trends but is still a "basecamp framework", with some additions to also be a "hey.com framework".
Basecamp is a small company, intentionally, so it makes sense that DHH is more of a "product guy", or at least has more of a product sense than your typically insulated enterprise engineer.