I really don't understand how you guys see it but 15 years is a very long period, that's about three circles with about one year left to make it four complete circles not everyone can wait for that period, lots of People sold a good percentage of their bitcoin before the price even got to 50k.
Moreover Bitcoin didn't just pump from 0- $108k ATH it took a gradual process before it got their unlike most other pump and dumps like the Trump coin that pumped then dumped and it finding it difficult to recover again.
I think what quotes posts are actually trying to address is simply, bitcoin rising to $108k in 15 years is not slow rather it is more like a bargain, the reason many people say this is because that is a 100000x move by bitcoin in that year as such there is currently no assets that has done that in a short period of time and has survived the drop. Bitcoin has had its hassle like government policies all against it but it still managed to survive the negativity and move such a price in less than 2 decades. There are globally accepted assets today that couldn’t do that ROI in such a short period of time, that’s what the quoted post is about.
Yes even in the process of it been volatile it required patience because many will have been fazed out by some certain dips that it did during this years but overall the ROI is still not that slow considering the years it spent