I believe you can not tar all in-house trainers with the same brush. There are a many "professional Trainers" that would fall into the same description that you have given in-house trainers. I personaly know several companies that I would stack thier in-house trainer up against any out-house trainer that you pick.
The wole basis of training boils down to the person that is picked starts with a deep commitment to safety, is given the tools to work with and has the backing of the organization.
It truly does not matter if you are an in-house trainer or an out-house trainer when the house realy does not care about safety both types of Trainers are destined to fail.