I think they did have influence in the bull run in 2021, but they were much less one of the main factors than in 2024, because of course the US market is much more important. But also in 2024 I think the ETFs were only the main driver in a short period, basically it was a "buy the rumours" event. When the ETFs finally launched, the rally continued a bit more but then waned because the inflows were still rather weak.
Yeah, I agree with this. The US ETF was the main reason we were able to get to a new ATH of 71k before the halving. At that point, it brought in a lot of hype and "hope", so the price just kept on increasing, because even before it was approved, there were rumours that it would be approved, and that created a demand that made the price start to climb. But it was only for a short time. As usual, people exegerrated it's impact and predicted that we would see Bitcoin at $200k because of the ETF approval, but they were evidently wrong.
If I remember correctly, the price dropped back to the 60k region and stayed in that region till months after the halving,, till like November, when it started to climb above 70k again.
So yeah, the US ETF approval had a big impact, it probably was what pushed us to a new ATH of 72k at the time, but the halving had a bigger impact. The hype of the ETF was short.