Actually, I agree with your point that a 50%-ish correction is not necessarily unrealistic, but we already had a 40% correction, recently, and there still remains a decent amount of uncertainty regarding the severity of the threat of any of the upmanship attacks on bitcoin... yeah they keep upping and upping the ante in terms of their attempts for destruction and disruption, but in the end, are these threats going to materially play out in a meaningful way? In that regard, you better fucking hodl onto your coins because even if we are getting down, we may well get up before we get down... so you are going to want to sell some more priro to any potential 50% or greater correction - that may well come after a further pump - even a 2x pump.
So no one is saying that BTC is the be all end all coin.. or that these attacks are not likely to have any effect.. but it is a matter of when.. and what might happen first before the supposed calamity that you proclaim kicks in.
Even a sudden 50% correction would be not doom &gloom. Quite the contrary for those prepared for it and still long term bullish.
I already posted before why a significant correction looks due soon (we had a couple recently in july and september, and now the price is quite high above the 100-day SMA looking ripe for some cashing in). Moreover the technicals and candlesticks patterns at this moment are not so bullish.
So I'm now keeping some cash on exchanges, which is not so bad (unless it's finex: https://medium.com/@bitfinexed/wash-trading-bitcoin-part-ii-who-and-why-is-someone-wash-trading-on-bitfinex-e1c7b5e0b3bb ). If I won't use it to buy cheap coins I'll find other uses for it. The hardliners who are all-in instead will be REKT at the first major correction and will have no dry power to spend on cheap coins (or anything else).