Well yeah the 2020 halving is also 'priced in'. Everyone knows the economy behind Bitcoin production and inflation. Knowing from the start when halvings in production are taking place and having a cap on the total money supply is why many people are here and why many speculators forsee an increase in price over time as long as new money >= coins wishing to be sold.
Yes, nothing happened after the first halving when the price was $9 because it was priced in. Nothing happened soon after that. Can't fight science.
Within 6 months after the last halving bitcoin went up 10 fold, within 12 months it went up 100 fold. Nothing is priced in since monetary good pricing is subject to a huge amount of inertia (stock-to-flow ratio very high) but when that inertia is overcome by pricing at the margin (true demand/supply) the new level can be very much higher and fueled by pricing perceptions and a large amount of speculative psychology.