I mean it’s not just file format problems as well. It’s also the fact that generally you’ll need a professional license for whatever software you’re using since you’re not using it for personal use and it’s probably cheaper and easier to buy a ton of licenses from one company then splitting it between different companies based on what people want. There’s also the fact that especially for bigger companies they’ll have custom tools and templates already made that work in that software. Some of that is file format for things like templates but any custom scripts or tools would probably have to be rewritten to support other types of creative tools. Plus at the end of the day it’s just easier if all of your employees are using the same tools so they can collaborate easier and ask for help on things easier.