The big problem is this, if we related this back to software it would mean the software being delivered in 10-15 years, rather than in 6 months. Kind of a big downside...
Not necessarily. For one, relating this doesn't remove the ability for incremental development. Another thing, there's very little actual innovation in software being done. Almost anything we use existed in some version in the past two or three decades, and it was much more faster, even if rougher at the corners. Just think how many of the startups and SaaS projects we see featured on HN week after week are just reimplementing a feature or a small piece of workflow from Excel or Photoshop as a standalone web app?
That's the old Ruby on Rails argument. In that specific case it only made sense when there were no similar frameworks for faster languages, but that's hardly the case today.
Ironically though, I'd be willing to bet that end-user performance on most traditional server-side-rendered apps using the "heavyweight" RoR framework is far better than the latest and greatest SPA approach.
In a previous life I did back office development for ecommerce. We had two applications, one RoR monolith and a "modern" JavaScript Meteor SPA. The SPA was actually developed to replace the equivalent functionality in the RoR application but we ended up killing it and sticking with what we had. Depending on what you're trying to accomplish server side rendering is just as good, if not better than the latest and greatest in client side rendering.
