I don't think that potential reputational damage should be used as an excuse for monopolizing software distribution. Sony can have a tightly curated PlayStation Store and build its reputation around it without that necessarily implying that nobody else may sell software for the hardware. "Bad third-party software might exist" (we have examples of that existing on the PS Store anyway, but I digress) is an argument for giving consumers ways to distinguish trusted software from untrusted software, not automatically an argument for eliminating the competing distribution channel altogether.