Professional wrestlers can work with whichever wrestling promotion they want these days if they are famous and the fans of that wrestling promotion want him/her. Some wrestlers get stuck and continue to work for a wrestling promotion which they do not wish to work.
WWE wrestlers in particular continue to work for the WWE as they are paid really well. Indie wrestling promotions are getting famous recently and can afford to sign famous superstars as well, but only a few. Eddie Edwards is a very famous Impact Wrestling wrestler who recently re-signed with the company.
He could have left Impact Wrestling to work for a bigger promotion but he chose not to. He was as guest on the WINCLY podcast where he stated that he is very happy to be at Impact Wrestling. He also mentioned that he did not even consider joining any other promotion.
On the WINCLY podcast, he talked about his goals and that he wished to be the world champ one day. "The main goal is always that World Championship," Edwards stated. "I want to be the guy up top and I want to be the guy with the company on back going forward, but hey, whatever I need to do to get some gold. Whatever I need to do to benefit the company, whatever I need to do going forward I am happy to do”.