300,000 km is about 186k miles. I've seen a few Priuses (don't know if that's the proper plural) go over 250k miles, or about 400,000 km. If you're planning on keeping it, as your post suggests, I'd change it every 30 - 40k miles, or 50 - 70,000 km.
Using M1 and going 3500 mile OCI is a bit too soon and pretty much a waste of money. You engine won't know the difference between 3500 and 5 - 6k mile OCI. As long as M1 doesn't burn in your engine, you're good to go. Chances are you'll never have an oil related issue. If something goes :poop...
It's a hard decision to hold someone accountable for doing, or not doing, something that they've never been trained to do, and perhaps simply don't know. When one is not trained and equipped for a certain situation, the result is always panic. It's a tough call for the judge.
Mike Nesmith of The Monkees passed away.
https://www.msn.com/en-us/music/news/michael-nesmith-of-the-monkees-dies-at-78/ar-AARH2mq?ocid=hplocalnews&li=BBnb7Kz
Cars and SUVs are only a small part of their portfolio. I've ready they've diversified in other areas and aren't too concerned about their ever decreasing personal vehicle market. No reason why they couldn't stand with Honda and Toyota, but they've chosen not to.