While i wouldn't mind towers offering a bit more protection, atleast early on, I don't think that video is good evidence.
Heca had two levels on that lux. IF a jungler is 2 levels ahead of the midlane(actually highest level in the game) at that point, it means he's FED.
Also, he does loose about ~60% of his hp to just the tower, and barely gets away with his life in the end. Yes towers should offer protection, but you need to do something yourself aswell. Lux didn't barely take half his hp on her own, towers shouldn't do all for you, they should be about as strong as another champ at that point, and it actually did contribute more damage than that lux that landed all she got.
If that Wukong that was doing wraiths duering all that time would have moved his ass 1 screen further, heca would have been a free kill and lux probably would have survived despite heca beeing really fed.
who had only jungle cinderhulk + mercury treads and a long sword NO armor item
He clearly had sheen and phage as he has a speedboost that refeshed on every AA and sheen in his buff bar, and given his lead, i probably even was a finished trinity. Also, tank masteries.
To be honnest, i htink a really fed diver diveing an vulnerable unprotected champion with no flash(atleast she didn't use it, else she'd have survived it) succesfully at post 20 min is totally fine.
My only issue with turrents is that i don't feels save under them even as early as lvl 3 vs not fed opponents, because a combo like renekton+elise can easily dive you from ~70%hp at that point.
Lee post 6 can just wardhop over a wall, kick you out of your tower and follow with Q...beeing under your tower doesn't feel save even pre 10 min vs any off the early junglers, and that is an issue.