It appears that there is now a tool that can allow unfocused vessels to run physics updates. This can most likely be used to implement failures for unloaded vessels, although this is obviously going to require a HUGE overhaul of every single reliability value.
An idea that was floating around was to have 2 "modes":
"hardcore": the reliability is set and everything is simulated as it should
"light": the reliability adjusts automatically with the number of flights in progress. If you multiply the MTBF by the number of flights, this should keep the overall MTBF of all your active flights pretty much constant and probably make the gameplay less irritating.
It appears that there is now a tool that can allow unfocused vessels to run physics updates. This can most likely be used to implement failures for unloaded vessels, although this is obviously going to require a HUGE overhaul of every single reliability value.
An idea that was floating around was to have 2 "modes":