The reason such simple reasoning applies to widely and true for centuries is that it applies to humans who deal the prices and thats key most of the time. Purely in a logical determination only you are not incorrect to assume less supply brings a higher price.
The explanation is that BTC has speculators, most markets do and they know ahead of time the supply will be lower. People buy ahead of the news and the price rises in proportion before the event. This isnt a one off, its almost every time you can expect some similar fashion of movement to this.
after all if you are early, that means you get best opportunity compared to others and probably gonna make a ton of money moving forward.
but this words especially holds true when it comes to current condition, halving are already hyped up since back then when the price of bitcoin was still sub $40k, i'm sure right now people are more focused on the other thing such as waiting for the rally to finally comes in.
we just have to wait and see whether these fomo investors will be able to stand it or not seeing bitcoin prices become unstable in the next few months.
the timing currently is just not right so there are many people holding back from further buying probably waiting for the right time.
but it also means that if we are diamond hand, buying right now might works wonder for future.