I think I posted it before, but I had SPA using Spring Webflow running in dom nodes (no iframes required) with animation event handling, csrf, all back around 2006 or so. The calling html was also pure save for a jQuery include at the top and my app include. The backend used JSP. No back button issues, no client or server state (I used a db instead of some options webflow gives you), it was a dream. Completely lost on the company I worked for at the time. I was up and running with a new user flow, in half a day or so. Static blocks suddenly would "do stuff" from the perspective of the business team in about half a day.

This is the problem with technology. When it works well and really solves the problem, it is invisible. No one gets promoted for invisible.