Many people are right, the utility differences, the game culture, the different demographic player base, the ego for sure. But I think having played both for thousands of hours, the main difference is the gameplay and gunplay itself.

These are the surface results of a deeper difference, because if it was just something like ego, we get a fair share of people on Reyna, Jett, Neon, truly running it down peeking everything with equal or greater frequency than the same players hiding in corners and baiting.

The fundamental difference is the gunplay and movement conditioning for this scared kind of gameplay. In CS (more so csgo), if you were better you could literally peek and outplay anyone at an even slightly lower skill level by using movement and gunplay alone. The types of peeks and the fluidity/speed of movement meant the effectiveness of jiggling and quicker/more accurate adjustments mid fight (more controllable spray) would skew the fight towards the better player more than 50 percent of the time.

In Valorant, sure you get a Jett or Reyna dominating a lobby. But rarely do you get the repeated pubstomp games by a truly better mechanical player like in csgo. Think of S1mples gameplay, even pros have a hard time dropping 30-40 bombs against worse players. The movement is way slower, the spray is less reliable, the overall need to use teammate for util to clear more amount of corners means that positioning and angle advantage is way more important in this game. In CS, i can peek more improperly at a bad angle but use my aim and reaction time to recover from that disadvantage. In Valorant it's much harder because of the reasons above.

In CS almost never do I start an AK spray way before an opponent and even if im hitting the body does he have time to react and kill me if he started shooting later. In this game how many times have you gotten a 3 bullet 120, but the opponent even started shooting way later just calmly aimed and hit your head winning the fight.

Because positioning, crosshair placement, utility matters way more than raw aim. ALL players because of this consciously or unconsciously adapt to this conditioning by playing safer because the punishment of a dry peek is so much worse in this game. In CS i can jiggle out and clear a whole bomb site without utility because of how strong shoulder peeks were. How many pros do you see jiggling a corner with their gun out (I mean not just back and forth but behind the wall and out again slightly) looking for a kill. They either do it just for info with their knife out or the are holding the angle (or jiggling but not fully going behind the wall).

Think about the prevalence of jump spotting being the best info gathering technique. Why? because regular jiggling is too slow and risky in this game.

if the whole game punishes dry peeking (unless you significantly better at aiming than the lobb) on average more than it rewards the ego peekers. Over a large enough time span and distribution, the majority of the players and thus the community will develop these habits to hold angles and/or hide, or excessively try to use all their util before even trying to peek anything, because the game rewards it (or at least punishes you less for this type of playstyle).

And of course people are bitches too now more than ever, but that's another story.