My only question is why would anyone use Synthetic oil in the first place? Regular dino oil changed on a regular basis, (every 5000km or so), does a fine job. I have owned several bikes and have never used synthetic oil in any of them. My current bike has 130,000km and is running perfectly. Unless you are putting more than 10,000km between oil changes and are participating in the Dakar Ralley, you should not need to go to the extra expense of using a synthetic oil.
You answered your own question. I'd rather do an oil change every 8-10k than every 3-5k. And synthetic oil is a better product. Why wouldn't you use synthetic oil in a new bike? That's the real question.