Acquisitions: cull the managers

One other factor to consider is that if a company were to do multiple acquisitions and consistently behave this way (immediately lay off every manager of the "losing" internal product), it would likely create a not-very-healthy culture of fear and opposition to acquisitions.

That's not to say, of course, that underperforming managers should get a break "just because". Rather, it seems reasonable to say that their performance and future roles should be re-evaluated along with every other affected party's - and yes, they probably shouldn't end up leading the newly acquired team a la Collabra.

(Keep in mind that sometimes the internal product's lack of success is quite often due to senior management's decisions... the same senior management that makes the decision to acquire).

http://www.gigamonkeys.com/blog/2009/09/28/a-tale-of-two-rew...

On the otherhand in that scenario the incumbent product was successful where the acquired company wasn't, which is probably more the reason why it was a disaster.