I’m assuming uralsolo is talking about free software as in, software which gives users the four freedoms.
I don’t think all software needs to be free, but in some ways, it’s no longer the issue of the day. In this day and age, a lot of what we’re using is no longer really software. We’re using services with client-side Javascript which is nominally free software (but not really). Most of the actual software is sitting behind a server. I see this as good and bad. It means users of less popular operating systems get access to the same services as users of popular operating systems so long as they have browsers, and the negatives are, well…I’m sure you don’t need my help to think of some.
It’s hard to make money with free software because everyone has the right to commercially exploit it. For this reason alone, I don’t think it’s necessary for all software to be free, but I’ll be there to celebrate the programs that are free.