One could also argue, this class of websites is what the majority of the website/webapp landscape should be. An average SPA is, in the end, a website for most

One could also argue, this class of websites is what the majority of the website/webapp landscape should be. An average SPA is, in the end, a website for most users. Take a payment form for instance - we had those 10, 20, 30 years ago, with 0.1x the effort. Of course there's place for fat client tech, but there are 1000 websites for each 'email client' - exceptional cases often dominate the discussion.