You can be a fake academic and build a career on plagiarism. However, stealing someone’s identity is dangerous, as academic fields tend to be quite small social networks, and someone is bound to notice. It’s also much more difficult to wiggle out of identity theft lawsuits than universities’ ethics rules.
It tells us something about psychiatry as a field. Imagine faking being a programmer or a physicist for 20 years: a trivial Fizz Buzz-like test would reveal the truth for the former, and the failure to reproduce research results—for the latter.
At massive (non-FAANG) companies, it's more common than you might think. Surprisingly.