It's possible if a bitcoin ETF were to ever be approved that it becomes the catalyst of a bull run. It will not be the cause of the bull run though, as that is dictated by market cycles still.

Personally, I think that bitcoin ETFs will come as a matter of time. However, I don't think that short term prospects are that good at the moment for any ETFs approvals to be incoming our way, as the previous rejections of various ETF proposals in recent years have suggested.

Also, it's important to note that ETFs will likely not contribute tangibly to the development of the bitcoin network, but rather be somewhat of a point for traders to hype up. At the end of the day, it's going to be a tool for institutional investors to make their money, it's not going to increase the network's capacity or anything like that.