They don’t, HBO is acutely aware of the motivations of pirated content, and even more aware of the challenges they’d face being a stand-alone provider. Not trying to single your comment out but I see this sentiment all the time with HBO. They’ve obviously done the math and concluded that at this point they make the most money by subscription fees to cable providers, DVD and Online sales, then they would - if they started offering every show for sale at the same time as air-date, likely diminishing their cable subscription fees.