My platform has moderate success (multiple games released each day), but to compete with RPG Maker means being 10x better. I was hoping to grab some of that market, but marketing wise it's incredibly difficult.
After its creator raised €100,000 to release it under the GPL, Blender became the leading open-source 3D tool it is today.
And they make enough money from recurring donations, service subscriptions, merchandise, conferences and trainings.
There are/were plenty of open source RPG makers, but they never gained any real traction.
I considered open sourcing my product in the past (did so with a previous game), so maybe one day. I still have some big things planned :).
* Step 2: Open source project
* Step 3: Find other streams of revenue (donations, grants, subscriptions, sponsorships)
Plus not everyone wants to give their product away. I see that advice all the time here and reddit and other places, "just opensource it" as if that's a solution to every problem a creator might have. I even saw it on a gamedev subreddit where a guy was asking how to make more money and people were saying to make it opensource, as if making it free would somehow increase sales for him.
I'm not sure if we had that perfect storm in game engines yet. Unity fumbled big time, but Godot wasn't quite mature enough to fully take advantage of that opportunity.