In corporate environments, there is too much management bureaucracy. A person with lots of ambition entering a weak or insignificant subsection of the company can quickly feel out of place.

However, when you have the veterans who have already done something great, an ambitious person may seem like a rare opportunity to do something big again.

In the words of Ip Man, it is difficult for a student to find a great teacher. It is more difficult for a teacher to find a great student.

Can be, if it seems likely that the ambition would cause them to leave the company, especially if within a year or 2 of hiring. There are a lot of costs to hiring someone (both money-wise and in opportunity cost) and if they seem likely to leave in less than 2 years than the company could end up net-negative for hiring them.

It can be.

Too much ambition can lead to losing sight of practicality, burn out, high stress, anxiety, depression, high turnover, as well as losing site of the bigger picture.