Depends what you're building I guess. Most Rails devs work on Cruddy / SAAS things like Basecamp where Rails is more than fine (or Django / PHP for that matter)

Depends what you're building I guess. Most Rails devs work on Cruddy / SAAS things like Basecamp where Rails is more than fine (or Django / PHP for that matter). If traffic is extreme caching can solve a lot of the problems. Also, companies like Shopify/Github open source and merge to Rails much of their scaling solutions, it's not as if you start from scratch.