As a developer of enterprise SaaS applications, where the core functionality is hidden behind a login, I could not agree more with most of this article and many of the comments as well. Being able to operate in an environment immune to the challenges of SEO should in theory free developers up to choose different tools for the job.
In my experience (and I imagine others would be inclined to agree), most developers want to use the tools and languages they are most comfortable with. When we consider the reality that most developers are used to working with tools usually relegated to backend development, a barrier gets created when these developers are tasked with working on Web Based Applications. These developers are going to approach Web Apps using the same backend\server-side rendering tools they are comfortable with and basic human nature dictates that they are going to try to operate within their comfort zone.
This results in a situation which isn’t all that different from the “if all you have is a hammer” adage.
And all of that is fine, because while they dig their heels in to the soils they stand on, radical new methods of software development are emerging which may ultimately render their entire argument moot. How would one argue for the virtues of server side rendering when software is developed and hosted in a serverless way?