There are several ways to capture that state, and the nice thing is that the browser allows sites to either opt in or out depending on their requirements.
See: Insights, FullStory, or any other event hooking library.
We can also play back those actions using the very nice WebDriver apis available in modern browsers.
There is zero reason to assume that we've lost reification simply because we've moved away from an approach that requires at least one RTT in latency before updating what the user sees.
It's not something most users do, so if your argument is "Reification is not on by default for all users" then sure.
But that's a meaningless statement. Most users don't want that ability, or aren't willing to spend the 10 minutes it takes to configure.
Otherwise, you absolutely can enter commands and output state: https://sites.google.com/a/chromium.org/chromedriver/downloa...
Further, there are a HOST of tools that make this process very easy, complete with replay solutions, detailed logging, real time monitoring and all sorts of other fantastic, modern tools.
Just because you choose not to use them doesn't mean they don't exist. Sorry your understanding of web dev is out of date...
Though as you mention, many developers nowadays don't see the need for history, and so are putting application/webpage state somewhere other than the router. This IMO is short-sighted, as it undermines the transparency of a user's actions on the web. And plays into the walled-garden effect many of these same developers will lament in the loss of the "open web".