I think you are absolutely correct. I can explain the reason behind this Actually halving just reduces the pace of creation of supply of bitcoin and not the stock of supply reaction to this isn't immediate and it takes time for the market to realize this imbalance in supply demand and then price gets skyrocketed so no one is thinking that just after thr day of halving we will see the ATH. I would like to show a chart from my very own post which I created earlier depicting effect of halving on

You can clearly see the All time high was seen somewhere around the 30-40% mark of the market because only after that the imbalance of Supply and demand was visible. I would try to dig deep and see if there is some static formula which works behind this.