CANbus is really 'fussy' about hardware 'connections', has a lot of 'overhead' (lot of 'data' to ensure a little bit of data is good),if ONE module(computer) has a glitch or fails to respond within a timelimit, poof, system can 'crash'.More than 1/2 the 'problems' I've seen are hardware... gimpy connectors, loss of signal cause, well, cars and tractors do tend to bounce...DOH.,EMI glitches lockup the systems.,shorted wires/open wires, etc. due to poor installs. Underspec components(um, it gets HOT in a car in summer....) Sunset looped software....from the 'gee, it's not supposed to do that' programmers who have never ever seen real hardware or done low level programming. Someone could write an entire book on the flaws of Can, maybe fill a shelf.
There are others though the push now is for SPE (Single Pair Ethernet), cramming tons of data on 2 wires.'Should' be faster and cheaper.
My favorite though is a 4 decade old,slow speed, true single wire (plus ground of course), that I can get 15 miles of 100% reliable communications with 22 bits of information for every 24 bits. A break in the wire, is easily found and no loss in data with a 2nd 'backup' wire. Bad nodes, easily bypassed. never ,ever been sucessfully 'hacked'. It ain't 'fancy' but reliable.