[mlyle]

A type rating allows you to fly a specific type of jet.

So, if you know how to fly Cessna Citations and Hawkers--- and you move to an employer with Gulfstreams, you're going to need expensive, type-specific training.

If you have $100k in type-specific training for what's now a popular jet, your employability and value to new employers grows.

[gjsman-1000]

Also, bad for the employer that trained you, they may be employers willing to immediately pay you more because you have already been trained and so they don't have to bear that cost.

[lesuorac]

Do those other employers not already have employees that may move to your current/old employeer?

It's zero-sum.

[randomdata]

It is zero-sum when the employee burdens the cost of the training when they leave and makes up the difference in that higher wage in the new job, but that's what is considered a problem here. The suggestion is that a zero-sum situation isn't fair to workers; that the employer should both burden the cost of training and pay a higher wage to those already trained. That is not zero-sum.