You are saying that the enemy isn't doing anything in that time frame that Ryze is casting Q E W Q E Q. That is how many spells it takes to full to zero someone in the late game. Which takes around 2-3 seconds. He has short ranges. He is close enough for Fizz to dash on. That is how close he is when he is throwing out his spells.
In terms of poke, again. He is close enough for Fizz to get a dash off. If he is getting positive trades, that is because the enemy made a mistake.
When playing against Ryze correctly, you will break that shield and kill him very easily. Irelia did it super easily even after the passive nerf. Renekton did it easily. Azir/Anivia were great at screw Ryze up. Ryze was EXTREMELY good into popular champions like Yasuo, Talon, Zed, Ori, Ahri, etc. And was weak to non popular champions.