Sounds for me like productivity went down...
Which seems to end up meaning productivity has gone down when measured by "things end users of websites can do", even though modern FE devs end up creating much more code and html and css than "the old days". (Admittedly, if you include privacy invasion, user tracking, and various other requirements of surveillance capitalism, dev productivity has probably skyrocketed...)
Complex? We still call a function with a return value on a stackmachine.
Sorry for the negativity.
And yet, most homepages today can't be viewed without javascript. You are correct, for the end user the complexity has absolutely not resulted in better homepages but worse.