do you realize how long it takes to develop a game? this is a early access, indie company of like 6 devs. multi million dollar dev companies take several months to make new content, and years to make whole new games, with hundreds if not thousands of developers. mods take all of 5 minutes to a month depending on the scale to make.

theres over 100 mod makers, (probably somewhere in the 300-700 range) that dont have to create something from the ground up, but take the work and alter it to do what they want their mod to do. theres over 10x the amount of modders to developers.

and many games do hire mod makers. minecraft, skyrim, and hundreds of others.