Maybe because there are tons of patents on HDMI cables?
US6932640 Oct 22, 2004 Aug 23, 2005 Yun-Ching Sung HDMI connector
US7059914 Feb 20, 2004 Jun 13, 2006 Advanced Connectek, Inc. HDMI plug connector
US7192310 May 16, 2006 Mar 20, 2007 Cheng Uei Precision Industry Co., Ltd. HDMI connector
US20060148319 Mar 3, 2006 Jul 6, 2006 Advanced Connectek Inc. HDMI type electrical connector assembly
US8500489 Jul 15, 2010 Aug 6, 2013 Luxi Electronics Corp. HDMI locking connectors