Disadvantages of Conglomerates ...

Conglomerates are bad!

The main (and key) disadvantage is that it is very difficult to track where all the $$$ is going!

I myself am not a fan at all of this business structure - Korean chaebols abound with stories of dirty $$$ and of course ~ who could forget:

The Trump Organisation ~
https://en.wikipedia.org/wiki/The_Trump_Organization#Controversies !!

And there could be something for Microsoft to think about there - perhaps focusing on software rather than skewing out too much into other not so synergous areas - e.g. hosting, hardware etc ...