What people need to understand is IPTV still needs the source.
eg. Lots of UK streams come via UK Cable + CS and some tuner that received all channels on a transponder.
It's unlikely many systems capture the HDMI output from official Sky box due to HDMI protection issues, and more importantly how many channels? Hundreds .... therefore that many subs & official boxes... that's a lot of investments (multiroom in Buckingham palace?)
What will happen is the IP's will be added to some global block list, much like other pirates sites like already do. Rupert and co will be only too happy to comply on this. IP blocking will only be the first line of attack. Streams need uplinks, therefore the source can be tracked eventually.