I do think the next two games are crucial and should to some extent determine his fate. That being said, - I think a decent reason to retain a new manager is that chopping and changing a manager rapidly destroys stability and can do more harm than good. We have had a lot of changes at villa in the last 12 weeks, - bit of stability might not be a bad thing.
im not necessarily defending RDM, and I do think results have to improve given the cash spend but I do think the above is a coherent reason.