That's a completely valid problem, but at best it's debatable whether it applies to Ruby web frameworks. There's not exactly a plethora of mature web frameworks available. Rails and Merb seemed to be the most firmly established frameworks with a few others like Sinatra, Camping and Ramaze sprouting up.
I think the too much choice problem applies much more when you're installing a Linux distribution and you have to choose from 40 different text editors or IM clients. Who has the time or the inclination to evaluate each one?