The key here is that if we consider equivalent good and robust implementations, equivalent capable teams, same UX, etc of an SPA and a traditional full stack MVC application with a modern ajax tool such as livewire, hotwire, etc the latter takes a fraction of the time and cost to build and the result is far less complex and easier to maintain.

I've worked in both kinds of environments, and unless you're building an offline first app, dogma, or Google maps...SPAs make absolutely no sense from the engineering point of view.