SlimPort is offered license and royalty free. They would have to pay for MHL.
That is what a lot of people don't understand when you add all these extra features it add to the cost of the device with license and royalty free. I think that I read if they added a SD card reader it would add $10 per phone in license and royalty free before the added extra cost of the SD card reader hardware. LTE is another license and royalty free over 3G data.
The Nexus 5 has Miracast and Slimport for streaming TV. Few TV have a Mobile High-Definition Link (MHL) that is an emerging technology for connecting mobile devices to A/V gear such as a TV. The current implementation for TVs relies on a standard HDMI interface, which allows users to play videos in up to 1080p resolution and 7.1-channel surround sound.
SlimPort is an alternative to the MHL license, based on the DisplayPort standard integrated into common microUSB ports. SlimPort is offered both license and royalty free, and supports up to 1080p60 or 1080p30 with 3D content over HDMI 1.4 (up to 5.4 Gbit/s of bandwidth), in addition to support for DVI, VGA (up to 1366?768 and 720p at 60 Hz), and DisplayPort.
MHL adapters require external power while SlimPort does not require external power or extra cables and draws no power from the source to operate. SlimPort can use a common microUSB ports we charge our N5 with but MHL would require a different plug or converter cable. MHL adds a few cool new tricks. One is that it sends control data through the same cable, so you can control the portable device (Nexus 5) using your TV's remote that I have no ideal how that would be used. Other than the MHL cable provides power so your Nexus 5 won't drain battery while the media is playing I don't see any advantage of MHL.
I am sick of wires. What I want is for Google to allow streaming for my Nexus 5 pictures and short video's to my $35 Chromecast unit but when I want to stream a movie it comes over the wi-fi so it doesn't drain my battery and I can use my Nexus 5 as a phone while watching the movie.