Hourglass stops just about every ultimate, so what exactly is your point?
Also if Zed is so "hard countered" so easily. Why is he the #1 go-to mid laner in the game? Also dont pros still play Zed? Why?
Zed is the go to mid laner (as an assassin) because one by one, Riot is ripping the throat out of assassins, and he is the last one left standing.
The difference with Zed is that most other champions can perform their job without their ultimate. Go ahead, try and assassinate someon as a non-fed Zed without your ultimate. i DARE you. Because it isnt possible. Meanwhile, Fizz, Ahri, LB (20 cooldown, hourglass doesnt count that or Ahri's ult), Talon, all capable of killing without their ult (talon has the hardest time of those listed, but he doesnt get hard countered by hourglasses active, its a soft counter, unlike Zed).
The reason Hourglass countering Zed is a bigger deal than other champions is for a couple reasons: 1) you dont need to be quick or good with the active to avoid 2/3 of his burst. 2) It can stop his ult, and his entire combo because of the cast time on his ult.
Now, compare that to Fizz, Ahri, LB, or Talon (or even Akali). Sure you could Hourglass something of their combo. But Talon does his so fast you would need almost beyond human reaction time to use it against a competent Talon. Ahri does 2/3 of her burst while your charmed and incapable of using the active, as well as being able to save her second and third ult charge for when hourglass ends, meaning you only negate 1/3 of her ult. LBs ult is on a 20 second cooldown, so hourglass is useless against her in terms of avoiding damage.
Now check the cooldown of QSS. Now check the cooldown of Zed's ultimate. Now consider that it help 0 bit against Zed's poke - and that Zed can basically build a brutalizer for the cost.
You don't beat him cause you survive him, but you fall behind since he is a whole midgame item ahead when it comes to lane harass. He will outtrade you.
120/100/80 vs. 90 seconds.
What is your point? At level 16, he has a 10 second window to use his ult on you if you have QSS/mercurial. That is so small it might as well not exist.
And if as an ADC youre getting poked by Zed, something is seriously wrong with you.