1. No! [...]
2. I feel hope.
Isn't this a bit of a contradiction?

Hopium generator means for me that it creates hope, not that it is created by hope - of course the hopium can help to create the support for bear market bottoms and start the bull market, but the rest of the cycle isn't really determined by it.
This is the reality around Bitcoin with provable records.
It has been repeated 2 times (we can't count 2009-13 because there were lots of highs and bottoms back then). It could be evidence but it is quite weak, and we don't know if the second repetition really fulfills all "rules" cyclists usually mention. There were already rules which were broken before (e.g. the "rule" that a previous ATH is never broken in a bear market, was broken in 2022).
4. Bitcoiners rely on this cycle ideology for over a decade, and yet, Bitcoin keeps rising and creating fresh ATH. Hasn't that hinted something already? I only see positivity in every angle, which includes higher price over time and more investors coming in.
This would also support the hopium theory. However, there is also a negative side: the extreme profit takings after the cycle top, which may scare some investors away. I can only repeat that in the case of most altcoins, the ATHs eventually ended, despite of continuing cyclic volatility.
Since many are believing it, is it still a self-fulfilling prophecy?
The more believers, the stronger the prophecy.
As more halvings come, the value of Bitcoin (which I don't doubt) will go upwards. [...]It just means Bitcoin becomes very rare as time flies by, and soon more people are holding onto it, [...]
You ignore the sellers side here. Long term holders were according to chain analysis one of the main drivers of Bitcoin's crash in late 2025. Eventually they will want to sell, or buy a house or car directly with their Bitcoin. The supply of Bitcoin still will increase until 2140, halvings only reduce inflation.