I kinda have to agree. Obviously it will be investigated but, things like that happen all the time. Had the jet that was holding short of the runway moved into his path, it would've been easy for him to pull up and abort the landing.
As for him not being fit or too old to pilot an aircraft, I disagree. He's an experienced pilot with over 5000 hours.
I don't understand why you don't think this is dangerous.
He was cleared to land on runway 20 Left, but he landed on a parallel taxiway instead. Yes he has over 5,000 hours, but the fact is he's flying into an international airport and can't tell the difference between a runway and a taxiway means he is past his prime.
20 Right is 5700 ft long and 150 ft wide
20 Left is 2687 ft long and 75 ft wide
The taxiway to the left (Charlie) is even thinner than 75 ft.
He MISSED seeing a runway double the length and width of his authorized runway and thought 20 Left was 20 Right in broad daylight.
The runways are also clearly painted with a 20 R or 20 L on the end (19L nd 19R in old pics because of magnetic north shift over the years), have flare marks and centerline markings that distinguish it from a taxiway.
https://www.google.ca/search?q=john...e+airport+20+r+approach&imgrc=AejxvsOHOC8K_M:
https://en.wikipedia.org/wiki/John_...Airport,_Orange_County,_California_(2014).jpg
If that weren't enough, there was a Boeing 737 aircraft lined up on 20R ready for takeoff. That should have been a huge clue that the next strip of runway to the LEFT, was 20 Left.
Even small airports have a separate ground and air frequency. He would have had no idea what aircraft movements the ground controller would have been making because Ford would have been on the air frequency. The ground controller could have been moving several aircraft on or back and forth on the taxiway. The ground controller does not deal with any aircraft whose wheels are not on the ground.
As I stated earlier, after 60 skills dramatically decline for most people. The smart pilots set an end date to stop.