The Republican party fractured at that point ~ and not just into two parts but about half a dozen parts.
Many Preibus supporters were also NOT Romney supporters ~ which shows you the kind of fractures that party had to deal with. The firing of Steele ~ apparently for being there when Republicans won a big election created other fractures between RTL conservatives and the soon to be renamed GOP-e ~ they obviously weren't going to get together at all in the long run.
Without going into all the details, the Republicans set themselves up to be skewered first by the GOP-e and then by the Democrats, even as the Democrats began to spill disaffiliated Democrats by the millions.
Preibus provided little if any primary support to make sure all went well, and even less support to Senatorial candidates ~ particularly those who did not buy into his blind loyalty to Romnyism.
Steele happened to be in there, but had absolutely nothing to do with 10.