I don’t know what it’s like in other countries, but as Jagster and Steff will testify to age/experience is the main problem. Followed by where you live in the country, big Cities being the worst.
One of my Army mates lives in Brent, a suburb of NW inner London. He’s got a top of the range Indians, £1200 Fully Comprehensive it cost him.
In comparison, I live a 130 miles away NE of him, in a small old fishing town. Bike theft in the U.K. in cities is pandemic, but here it’s mainly twist and go Scooters and the odd 125 bike. So my insurance is very reasonable compared to my mate. I’ve just insured my R111 and my BSA A65 fully comp with recovery and legal assistance £290!