Comment by d3ad1ysp0rk

More likely to be a tech lead in those cases, or to be helping hold the project together while they are hiring a full time resource. Also in certain cases the companies are so far from ideal states that a lot of good can be done in 6 months. Overall, I agree that most times it won't make sense for a company to plan on switching dev managers or tech leads after < 6 months, but again that assumes ideal conditions or options.