Isn't this what it used to be like?
I haven't lived in Southend (Hockley really) for almost 20 years, but I can't remember the seafront being especially problematic for cyclists or drivers except for high season in summer.
I've commuted along there daily for the last ten years.
In my opinion what was the real situation for cyclists?
Experienced cyclists used the carriageway with ample space. You can see the old carriageway width captured on streetview last summer in traffic
linky - plenty more room than captured in last night's video (and note cyclist stopped to admire the view).
Inexperienced cyclists still used the road, seemingly without issue. A painted cycle lane might have assisted this "market group".
Families, children, and lots of others meandered along very slowly on the pavement
between the pedestrians. I am not aware of any injury collisions that took place, although the letters pages of local papers do tend to have anti-pavement cycling whinges regularly.
edit
captured on streetviewIf any of the other locals want to add to this then please feel free, but I would agree with alexb - I don't think that the seafront has been "especially problematic for cyclists " at any time.