Your analysis is quite right and I see lots of sense in what you have written but I want to pick on the third paragraph where you mentioned that “profit taking will cause price drop here and there which will in turn create panic sell” but to me, I believe it will not be that obvious, yes I understand that already existing investors when profit goes high tends to take profit.
But, don’t forget the fact that when the prices drops, more new investors will also tend to buy more too at the deep including the already existing ones who will still pump whatever profit they get into same market back, isn’t that what the big whales are playing and yet, the market has not crashed to zero and still doing well.
Yes, obviously there could be phases where the market is still bullish, so a little dip gets bought up (like the mini-crashes in the Bitcoin bullrun of 2016-17).
The problem is that there will be phases where the sentiment changes to negative, even without a clear "reason". For example, in 2019 we have a growing LN and many advances, but the price still doesn't want to recover. The only reason sentiment is negative is
because the price went down! These are the phases which go normally a lot deeper in PoS coins because there are so many people that have hoarded their coins to get PoS rewards and want to take profits - and if the bear market becomes longer than expected, like with Bitcoin in 2018, then many of them will sell even if they declare to be "long term bulls".
Generally speaking (from my observations) volatility is higher (and thus, crashes are also deeper) if there is more speculative capital invested (that means: capital that is meant to be sold for a profit in the future) and less currency usage. PoS itself encourages speculation more than PoW because it offers an "internal" profit mechanism via PoS rewards. So there is more effort needed to encourage currency usage/economic interchange/trade, which lower volatility.
However, if Bitcoin was already used massively as a payment means, then a change to PoS would have, probably, little to no effect to volatility. But I consider a change to PoS currently extremely unlikely - also because mining with solar/wind power provide a way to secure the blockchain in an environmentally-friendly way.