The situation you're describing is going to be far more about the specific personalities and power dynamics than anything related to accurate performance estimation.
I have repeatedly seen companies treat their contractors with lot of disrespect, such as repeatedly sending their salaries too late, or extending the contracts for the next year at the very last moment (in one case the papers to sign were delivered literally on December 31st in the afternoon). Some of those contractors were the best developers in the company. The company employees who did the paperwork simply didn't care.
In the most absurd case, the best developer got a contract offer from another company with deadline to sign at the end of November. He wanted to stay at the current company, and the managers were telling him they wanted him... but he was unable to get the contract extension on paper. So at the end of November, he was like "okay, screw it, I wanted to stay here, but I am taking the other contract, to avoid the possibility that I would miss that other offer and this company would not extend my current contract here". So he signed that other contract (starting from January), and when towards the end of December this company finally offered him a contract extension, he was like "sorry guys, but I already signed a contract with someone else". He left, and the managers were all surprised "but we told him we wanted him, why couldn't he wait?" During the following year, a chain reaction started, when his closest coworkers left too, then more people left, most of them reasoning like "I was already considering a change of job, but I stayed here mostly because of good friends at workplace, now that the friends are no longer here, I might leave too". The company lost most of their developers... because there were not willing/able to extend their best developer's contract two months before expiration instead of the usual one month.
Another example, this was an internal employee, there was a super talented guy, freshly out of university, but incredibly experienced in some technologies. Also super helpful, whenever someone in the company had a technical problem, they usually asked him for help, and he always helped. The whole company changed their technological stack based on his recommendations. Then, one day, another company approached him and offered double of his current salary. He wanted to stay, so he went to management, described the situation, and asked them for 50% increase (which would still be only 3/4 of what the other company offered him). The managers refused; as I later learned, their conclusion was that "a person this young does not deserve such high salary". So the guy left.
Maybe this is "specific personalities", but those personalities seem quite frequent.
The situation you're describing is going to be far more about the specific personalities and power dynamics than anything related to accurate performance estimation.