ISO doesn't write the text of the standard, that is done by members of the individual Technical Committees and Working Groups.
I am currently a member of TC184/SC4 and have also been a member of TC22/SC31.
I am currently a member of TC184/SC4 and have also been a member of TC22/SC31.
For the TC22/SC31 work I was just being paid by my employer and they provided the travel costs to meetings.
The scope of TC184/SC4 is much bigger, the core people work on it pretty much full time and get paid by industry consortia to deliver something that will meet their needs. Some parts have been written by postgraduate students who got their PhD out of the work.
If they write the text of the standard, that means ISO writes the text of the standard.