Ruby is meant to be a very productive language. It does waste some server resources, but the biggest cost for any project—especially early on—is in development hours, not hosting. Hosting typically costs between 5% – 10% of the monthly development cost. Using Ruby helps us build what we need quickly so that your idea can be tested and tweaked while using fewer development hours. Once product-market fit has been found and the business optimizes more for cost and less for time, moving to a different, more verbose, performant, and less flexible language makes sense. But that’s usually several years away.