My experience from lessons learned over the past ten years is that SPAs generally take longer to build, are usually slower to load, have much worse accessibility and are more expensive to debug and maintain.
For a great deal of web projects you're better off with the "old paradigm".
That said... I do think there's an argument to be made that Django should include core framework features that make working with SPAs easier, rather than farming that out entirely to Django REST Framework.
Django 4.2 does have one nod in that direction: https://docs.djangoproject.com/en/4.2/releases/4.2/#django-c... - "ManifestStaticFilesStorage now has experimental support for replacing paths to JavaScript modules in import and export statements with their hashed counterparts".