People mostly just use software. Software is either good or bad. It's either monetized or it isn't.
This is true, but also, this ideology is mainly seen in Windows of macOS users - these users they just use software.
But there most certainly is a "world of open source", and you usually enter that world when you switch to an opensource OS like Linux. And the reason why it's a whole new world is because you'd predominantly use opensource software on such an OS, so you're going from a world full of mostly proprietary software, to a world full of mostly opensource software - it's a stark contrast.
So usually, at least for me, any talks of entering the "world of open source" usually begins with switching to, or trying out, an opensource OS. At least on the desktop.
On the mobile space however, particularly in the Android world, there's been a growing awareness and desire among the privacy conscious people to switch to opensource apps. More and more folks are tired of the ads and tracking and privacy issues that plague proprietary apps typically found on the Play Store, so people have been increasingly looking towards opensource apps, which are free from such annoyances, and as a result, opensource stores such as F-Droid and Droidify have been gaining in popularity.
So there's most definitely a world of open source out there, and the first step into that word usually beings with people getting fed up with corporations screwing them over, and thus looking for alternatives.