I'm not the person you replied to, and I can't speak for them. But I can say that for myself, and a not small number of other people, it's an ideological issue. I simply do not use software that isn't F/OSS - to the greatest extent that that is possible. For me, I might use a VERY small amount of non F/OSS stuff, but it's very hard to get me to adopt something new if it isn't.

Now should you make business decisions based on that? Probably not. But while I don't claim to be a representative sample, I am pretty sure the number of people who share my beliefs in this regard is substantially "non zero". shrug