> The more of these components that become readily available, the more impressive the starting point for any future indie game.

I'm not sure to what extent these things can be recycled(other then for ideas).

Actual advantages I see:

Fixing bugs/maintaining long term/packaging. This allows people to spot bugs easier, contribute back code, and generally maintain the game better(fix anything that break thanks to old platform assumptions).

Porting to other platforms(especially arm, maybe android these days), many who open source games allow you to use a copy of the data for one platform on any platform.