Earlier quoted context omitted.
Person currently earns $80k. Training costs $20k. Rival company will be willing to pay $90k salary after training to poach the developer, which means the current employer may end up forced to counter offer with $91k salary after paying for the training. 91k + $20k in training fees = $111k Competitor does not pay $111k because competitor does not pay for training. Which was the entire point of the exchanges above You…
Nobody is asking how to add numbers together. I just think you're missing the point. Whatever a competitor is willing to pay, the company that provided the training can just pay that and not risk their employees being poached. Additionally, it isn't free to poach employees, they will have training costs no matter what. In other words, after training you raise their salary.
And hence, in the original example, the company providing the training ending up spending $111k on their member of staff over the course of the year to head off a competitor's $90k offer, even if the employee isn't worth $111k (Considering your original contribution to the thread was to argue the competitor wouldn't pay $111k, I think accusing me of missing the point is a bit rich...)