Indeed, after all what would be the point of going through the trouble of acquiring a company if major changes weren't coming ? If you don't need something special, there is a myriad of other option from simple client account to investment or the various partnership level, including shared owned subsidiary for R&D/other.
(Though this isn't necessarily intended to deflate any fears about IBM meddling at Red Hat; for a company as important to OSS as they are, any change is worth being wary of.)
AB was a profitable company, but InBev is just very good at efficiency in brewing. IIRC they paid handsomely above market price at the time and were able to translate their efficiency to AB in such a way that the combined reduction in cost and uptake in revenue creates value net/net for InBev (and therefore AB)
I doubt something in engineering and sales? Or perhaps sales is the closest answer.