Since I still believe in a cyclical nature of markets / humans, how long can a cycle be? We still need some time to go from overvaluation to undervaluation, so I would guess a cycle will be still between 3 and 6 years or at least between 2 and 8 years.
I've already mentioned somewhere else that it could be possible that this behaviour is similar like fads work in the consumer goods market, which would be probably what you call "time". So basically it could be based on the collective attention Bitcoin gets at a specific point in time. Fads can't be constant, they need to "sleep" eventually, but they can always come back again.
The halving could have been in this case not only a psychological trigger (and, in the first occurrances, a trigger due to the decreased new supply provided by miners), but also the media attention could have triggered part of the increased attention, and thus the increase of new users and investors, leading to the post-halving rallies we've seen in the past.
Then, like you wrote, it's possible that above all downward movements are amplified due to service provider (e.g. exchange) insolvencies. Terra/Luna for example also probably collapsed due to a chain effect in the bear market, even it was a questionable product from the start.
It is possible that at least these "volatility amplifications" could reduce if the markets for these services mature further. It could be interesting to generate a timeline how many exchanges collapsed per year, multiplying the number with the market share they had. Also stricter regulations for exchange reserves could contribute on that, but FTX (and cases like Wirecard in Germany) showed how even regulated companies can collapse due to bad intentions of the company owners and/or managers. So we shouldn't rely on regulation alone. The "learning effect" of customers to not put that many funds in exchanges and centralized wallet providers is in my opinion more important. The declining BTC exchange balances are perhaps an indicator for that, however measured in USD they're still growing.
There could be also an influence on "real economy" cycles on Bitcoin's cycles. While I was aware of the likely influence in 2021, I wasn't that aware about the 2018 bear being influenced by a real economy factor. Central bank decisions (interest rate) are for sure important.
In general, however, these points you've mentioned are mostly influencing "investor" sentiment, i.e. of people wanting to profit from Bitcoin. If Bitcoin wants to establish itself for the long term, however, eventually people must realize that Bitcoin also provides value if its price does not grow anymore. Thus I'm so focused on the "currency usage" aspect in this thread (and several others), i.e. in usage for payments and low-risk/low-reward saving. We probably have some time for that to occur still.