You are right about CS having a steep learning curve. However it is highly improbable for a team to do well from the get go. The so called tier 1 Valo pros have taken a lot of time to set in and start dominating. Take a team like T1. They played the game very slowly and depended more on gunplay rather than abilities in the beginning. They were half-decent and completely got obliterated by teams like TSM and SEN who adapted to the game very differently. Do you think it is possible to get the spike down in CS within 10 seconds? I don't think so. Valo has expanded to boundaries which CS can never imagine. A viper can literally camp spawn the entire round and still clutch the round with only her mollies.
The meta keeps changing every 2 weeks with a new patch. By the time a team settles down in the meta of one patch, a new patch is already out with mechanics just to ruin your game. People come up with new tactics every day. Having watched Valo for nearly a year, the difference in how teams play now v/s how the teams played back then is huge. Wall boosts, New lineups for every agent, outplay tactics are being discovered every day. Navi is the best team in CS now, but if they enter Valorant now, a Raze with double satchels and a Judge is enough to destroy them.