But this time it's different. Redhat is opensource ... which means that the biggest asset that RH could possibly bring to the table is the knowledge in the heads of its employees. If they are gone, nothing is stopping them from joining CentOS team or perhaps setting up a new distribution based entirely on RH (also with commercial support, because they know how to do it).
But I think this deal is about something else. The winner here is Power CPU architecture, which will receive "virtually unlimited" support from the favourite distribution of banks and other large (and medium-sized) institutions.