I have worked for two of the Big 4 consulting firms, in security domain. They have the same story - they promise client to provide resources on subject A and B, ask the ones who have less project to learn subject A and B (these resources are expert in subject X and Y, but since the client wants A and B - they are asked to learn that in a day or two. I have seen many colleagues going to the client location, searching on Google "how to do A" in the morning and then provide some PPT with basic information.

Currently working for an American software dev company.

What I mean to say is, the issue you mentioned is not limited to these 5-6 companies, but for the whole IT industry.