Agreed, one can't say that all PIs work the same, it isn't true.
Also, some do have the best of intentions, but don't have the skills to facilitate their student's career.
In a sense, each lab is a small business, and I think this is exactly what needs to be taught to a new professor. It is a real shame that this isn't taught. People management, money management, and resource management are skills that some people, regardless of how brilliant they are, don't have. As it would in any business, these attributes ultimately lead to a lab that is run poorly. The really bad thing is that these labs continue to operate, which is a huge waste...especially when talking about federally funded labs.