This is a software problem, not a Rails or even a Ruby problem. I've seen Java/C++/C# systems collapse under their own weight just as often as Ruby/Python/PHP b

This is a software problem, not a Rails or even a Ruby problem. I've seen Java/C++/C# systems collapse under their own weight just as often as Ruby/Python/PHP because they don't invest the time in cleaning up the tech debt as they grow. Parent is definitely right, projects that are "designed right from the beginning" do not exist in reality. Everything has unknowns in the future, and it is better to be flexible and adapt the code base to them as they come rather than trying to plan everything out from day 1. Static typing does help with these adaptations, but it doesn't compensate for a lack of diligence in keeping the code clean as the software grows.