Doesn't matter? An approach is an approach? Very Alaska bush attitude there.. be careful. And be sure the FAA thinks the LDA-Z is different, so much so that is requires individual crewman training on it. But again what do I know.. I've only had to do it.
Yes Delta can develop their own RNP approaches, but having been around for Alaska's development, there was a jet parked in Juneau for months just dedicated to proving runs. Also FAA Flight Check does not do any of the RNP checks, Alaska was back up just a few weeks ago doing proving runs and flight checks for some minor changes and mag var updates. Non of this stuff can be done in the sim for operational approval. Alaska pilots do their initial checkouts in the sim, but then they still must be checked out doing the actual approach, and then are only high mins qualified. There is a process to get low mins qualified and to keep that qualification.
Yes Delta can send people up to Juneau.. but where are they going to set up shop? You have obviously never stepped foot in the Juneau Airport but still question people that know every square foot of it and know there is no space for lease for a 135 let alone a 121. And again the airport management was quoted in the Juneau paper that this was a complete surprise to them.
As for Delta doing it have assed... study some history on their last attempt at trying to break into the Juneau market. That is one way in the Alaska is actually unique.. people are not always drawn to the cheap ticket. Dependability comes first, and one night stuck in a hotel eats that $100 savings right up. People have a long memory of Delta's last attempt in Juneau, and their dependability issues, even if Delta doesn't. And that is a big question among locals.. what is different this time? And if nothing, it will be another summer experiment and then adios again.
And the Alaska attitude. Let me ask what and where you fly and I'll tell you why your all wrong with out ever going there or doing it.