The problem being that Byzantium was a large centralized empire, so a succession crisis had disastrous effects that could change the region for decades to come, whereas in Western Europe, one count dying without an heir is not going to cause the entire system to come crashing down.
Yeah, the impression I get is that Byzantium's more centralised government meant that there was less endemic instability, but that periods of instability and weakness in the centre were potentially devastating. Something like the post-Manzikert collapse couldn't have happened in feudal Western Europe, for example.