Jeff, DP works with older 1.x HDCP protocol. DP 1.3 is also supposed to be compatible with HDMI 2.0 and the new HDCP 2.2 protocol as well.
HDCP 2.2 is only relevant for 4K content; it is unlikely that any new restrictions will be put in place on HD (720p/180p) content than what is already in place today so there really isn't any blocking issue for DisplayPort.
BTW here are the costs to implement HDMI:
http://www.hdmi.org/manufacturer/terms.aspx
- annual fee $10,000
- $0.15 per unit (discounted to $0.05 if using HDMI logo per provisions, and $0.04 if also implementing HDCP)
And HDCP requires separate payment:
http://www.digital-cp.com/licensing
- annual fee $15,000
- $0.10 per unit for key sets (discounted to $0.005 per unit if purchasing 1,000,000 key sets)