Their usual failure mode is they get loose enough so they "jump timing" , they slip a tooth or two on their sprockets, which are worn too.
I take it your vehicles with chains are NOT interference engines. If you have an interference engine and it jumps a tooth or two it WILL destroy your engine.
The real weakness of the timing belt is the cost of replacing them, not something consumers look forward too, and the fact that failure can total an otherwise still serviceable car
You don’t keep your vehicles long enough to know how much a timing chain costs. So yes for MOST people like you the cost of timing belts is expensive. Of the past 2 SUV’s I’ve owned - at some point I would have had to replace the timing chain because they both had OVER 400k miles and the vehicle was still running good.
I plan on keeping my 4runner at least another 100k miles. It has 260k miles and it runs EXCELLENT. I wouldn’t hesitate to get in and drive to California and back. And I’m sure I’d make the trip without a hitch. So in 100k miles I’ll be approaching 400k miles. Not sure if I’ll to the chain or have it done. Not looking forward to that replacement either way. The belts on my Pathfinders…I could do in one evening when I got home from work and have it completed before I went to bed.