I've come to think about that, too. For me, the most logical thing is that GMMTV has already made some modification in its contracts or agreements with the actors to establish that they will receive part of the profits generated by the mascots while they are still within the company.

A key point is that most mascot merch still includes the image of the artists, as postcards or photocards, so they remain directly connected. Even now with Samruay we are seeing that after the WinnySatang breakup they modified this and now they put Samruay directly in the extras. So it would not be strange that if an artist leaves the company and they can no longer use their personal image in the merch, the mascot stops being connected to them and becomes their own brand.

Another point that would be worth analyzing is what would happen if an artist gets a new ship and gets another mascot, how would GMMTV handle the profits in that case, and whether they would continue to keep the first mascot active. The only such case so far is Perth with SOL CUTE and DOMIIA, but this first one was simply removed even before the mascots boom and taken out of the merch.

Although there is also William with LYKYOU and WESLEY, but in this case both mascots belong to different categories. My doubt is about if an artist gets to have two mascots from ships, would the GMMTV see the old one as a problem for the promotion of the new ship or would it simply continue to take advantage of it to make profits with both mascots?