To all the ones saying they are balanced, you guys dont seem to have used one yet...
Right now my caravans are pulling in 1.8k eachday, this is way way too much they earn themselves in just a few days and never losses.
So i would say they should die sometimes and as someone mentioned maybe make it easier to make the caravans somehow without breaking immersion, maybe send a messenger to a companion when they are back in a tavern.
On the other hand each caravan you made cost you a companion who could otherwise be serving in a war party that you could be using to bolster your own military power by forming an army. Parties also bring in income of their own which means caravans need to directly compete both monetarily and in utility as a military boost.
Then once you have one or two fiefs you have more than enough passive income and those caravans that are using companion slots start getting less desirable. I actually shut down all my caravans once I had a second fief so I could support more war parties and have more companions to serve as governors (not that having governors seems to do anything, which is a separate issue that needs to be fixed).
And as multiple people in this thread have said they do sometimes die and you do have to go find your now lost companion and spend another 15K to get the caravan running again.
If you nerf caravans to die more frequently than they do now there's a high chance they'll stop being profitable at all and then it will become an outright dead feature.
Rather than nerfing caravans it makes more sense to simply make other roles your companions could be serving more rewarding. Specifically governors who, as I said, don't seem to do much at all.