I suspect they see issues on certain engines and never on others. There is enough info to avoid blanket statements that toyotas or other mfg benefit from (i.e. need) 5K intervals over the whole product line.So you're a therapist and an analyst ... I'm so glad you've jumped in to help me better understand the emotional intricacies of an oil change.
There are numerous people with lots of experience working with Toyotas (and other marques) who advocate for 5,000-mile oil changes. They have piles of experience telling them that 5,000-mile changes are beneficial.
So now we have two piles ...
12-15k in my prius, 10K in my yaris, 12-15K on my friend's 2002 tundra (once 18K) and yearly intervals in my friend 2006 vibe. No issues.
Never seen anyone complaining about 10K being too long on a 2UZ or a 1NZ (owned two); perhaps certain engines are more fragile, i just don't happen on own any of them
If you do, carry on as you have indicated.