Re: Wise move financially? Perhaps. Culturally? Nope ....
IBM has long been the home of big chunks of bleeding edge and open source work.
And Red Hat has more-or-less always been Linux's corporate hat.
The two companies have a long history of collaboration: staff from both contribute to the same projects in an open source framework, including Linux itself.
There may be some upheavals, but this doesn't look to me like a complete clash of cultures.
And as for Fedora, isn't that a community effort outside corporate control?