Bitcoin investment is not like Ponzi scheme or other shitcoins that pump and dump or that will crash down rather the price will only drop and the drop of price shouldn't be a new thing or a thing of surprise to any Bitcoin investor unless you are trader that will panic and sell when the price drop.
Bitcoin investment is not risk free so saying that there is risk when an investor lump sum is what i don't get there is nothing wrong when an investor chooses lump sum it's also a strategy of buying Bitcoin in bulk at once since the money is available instead of accumulating it gradually which you can also be doing with the DCA strategy.
Yes you are right, Bitcoin is here to stay, it has proven over the years that it's very reliable, that's why I sees this current price as a golden opportunity that should be properly utilized to buying aggressively if you have the reserves funds to do so. It's only newbies investors or those with traders mindset that mostly sell anytime their is a dip out of fear, instead of accumulating aggressively if you have the reserve funds to do so, so panicking anytime their is a dip like this mostly boils down to the orientation a newbie investor have before investing, because anyone who knows how powerful and rewarding it is to hold for a very long period of time, he wouldn't even be contemplating selling off his Bitcoin holdings anytime their is a dip in the market.