I speculate there is a replacement warranty. With higher end goods, part of the reason the cost is so high, is they don’t quibble about replacements. And with contracts there usually is a replacement clause for gear.
For your other questions, I speculate very low. Everything with a lithium ion battery has this potential. I give it another 5 years before we aren’t allowed to fly with phones and laptops or they have to be placed in fire proof bags or something because one bursts into flames and forces an emergency landing.
