For my part, I don't have enough spare time to learn one of the big engines. They're too complex, and this is a hobby.
DragonRuby on the other hand is simple enough that you can start doing stuff immediately if you know even basic Ruby. That is the appeal to me.
Whether or not it would work for a large team is totally irrelevant for that kind of use, because I have no interest in starting a studio.
It seems a lot of the people criticizing DragonRuby in this thread forgets that game dev spans from hobby development by individuals who might toy with it a few hours a week to multi year projects by major companies, and they have different needs and interests.
E.g. I value having fun over ever completing a publishable game. DragonRuby is fun.
That I could release something with it is a bonus, but to me even that is secondary.
So no, Unity is not "too complex" and it's very suitable for hobby use.
That I also don't have to use a language I consider absolutely awful is another major bonus.
You can see all the reasons
1. Their custom engine doesn't have all the features of either of those other engines. Their artists in particular are pushing to switch to get those features.
2. Their custom engine doesn't have have amount of tooling those other engines have (likely no blueprints, no shader graph, no state machine editor, no animation editor, etc..., etc..., etc...)
3. Their custom engine doesn't have tens of thousands of potential hires that already have experience with them.
4. Their custom engine doesn't have 1/1000th the amount of docs, tutorials, youtube videos, etc on how to use it so the team that maintains that engine has to provide that knowledge to every new hire
The result of the above is it limits their growth. If they want to start a new team for a new game, if they stuck with their custom engine they'd basically have to take a significant number of people off the existing game and move them to the new game otherwise no one on the new game would have any easy way to know how to use it.