The previous post cited the example of live-action production companies that are signatories to collective bargaining agreements. I neglected to clarify one thing -- most of those companies are not direct signatories -- they do not have individual CBAs with the various unions and guilds. Most are signatories through their own professional association, the AICP.
For VFX and animation companies of less than, say, 50 to 100 employees, it would generally be considered too troublesome and expensive to engage in collective bargaining directly. (Although I worked at a 65-person company in the early 90s that did in fact negotiate directly and at length with the local that represented most of its employees, so you never know what a given owner might want to do.) It would behoove companies of that size and smaller to form a professional association like the AICP or AICE, empowered to bargain on behalf of its member companies.
This is of course not a new idea. But it might be time to start thinking about it again.