Just like you don't want to support tens of different databases you shouldn't build your solution on lots of bridged message busses. If stuff goes down at 2 am you don't want to have to find out which message queue was the problem or what tooling you should use to debug it.
Sure, but it's an inconvenience, not a total blocker. With databases you lose foreign keys and you have to replace a single query with N. And you don't want to have ten different solutions of course, but two is fine and allows for comfortable migrations.
