Buying 1 BTC was realistic for many people before the first 3 halvings. Now that is no longer the case.
No one knows the future, and at that time, BTC was not as famous as now. Forget about the past, think about the future. BTC is still a valuable band; maybe someone will say in the future that 0.3 BTC is realistic in 2023.
Why would people invest loads of money in BTC after the halving and not before?
The answer is so simple. People choose to invest in the BTC market post-halving due to a reduction in its supply, which will increase demand, and you know that when supply becomes low and people demand anything high, it increases price pressure. Such types of events are a strategy in which investors look to invest based on historical performance.