That's nothing in bitcoin world. It routinely gains more than few hundreds percent in 3 years. It is also know to drop below 20% of previous peak price.
It hasn't been around long enough to "routinely" do anything on a three-year period. There have been 4 such periods. That's not enough samples to say anything is routine.
For something with this effect size, I feel like people can start making a case in the mid-teens, but you're probably at 20+ before you can make a strong case.
Edit: That's cycles. So I'm saying it's 2055+ before any case can be made and it's 2070+ before a strong case can be made.
I think it's important to notice that periodicity of bitcoin is not some emergent phenomenon happening for unknown reason. It's build into the bitcoin in form of reducing the rate of supply by half roughly every 4 years.
So do you really have to be hit in the head 20 times before you notice it spins?
So your claim is that a three year cycle is driven by a four year cycle?
Besides, the bust shouldn't be driven by the mining of new coins anymore. When a huge number we're being mined as a percentage of the total btc supply you could make that case. But now, the difference between generated btc now and after the halving is negligible.
But your overall point that causality linked to external factors is correct. It's just "the mechanism is halving the rewards" hasn't happened enough times to be valid because halving isn't reliable enough yet.
Actually, during the gold standard there were booms and busts every four years. Bitcoin might be on a different cycle but the constant inflation and deflation are actually expected with a fixed supply currency.
During the gold standard the boom/bust cycles were closer to a decade. Also, gold was a currency and Bitcoin is a speculative asset currently used for sending money to other countries and for illegal purposes.
