Every system of investment is risky and it is important not to invest or trade with emotions as one need to be focused regardless of what the outcome of your investments may turn out to be. Trading Bitcoin isn't that bad if actually one can follow some basic trading ethics and principles then you can actually makes some cool profits from it though buying and holdling is still the best option because you're in control of your bitcoin and for now the main purpose of inventing Bitcoin is to acquire it in our individual portfolio and hold it till it attains it's highest ATH then you can decide what to do with it.
Will I say that you are short minded because you sound more like a trader than someone who have the intention to hodli for long. What is the point of Selling all your bitcoin portfolio in ATH, what will you do with the money that can yield you a better profit than bitcoin in the next four years, after you sold it. You want to start all over again, and miss the benefits of the compounding profit that your bitcoin will generate for you. You should also put into consideration that the price of bitcoin increases with timeline, so if you were able to accumulate 0.3 btc and sell it during the Bull run at ATH. It will be very hard for you to buy back 0.3 btc with the same amount that you bought it then.
I'm not a trader but I've seen some investors that have been into trading Bitcoin and they are good regardless of the fact that they make few profits from it and moreover, how can an investor sell off all his coin when he knows that he can't buy it lesser than the amount he sold it so if any investor decides to sell off all his coin then he doesn't really know what investment is all about.
The way a child is given birth to and the parents will take care of that child for many years spending and providing for him to make sure that he grows up and become an adult who can take care of himself and also take care of the parents when they are old, is the same way we need to invest in bitcoin and grow it through DCA gradually as a newbie so that a time will come when your bitcoin portfolio size has is big. Your money that you invested into bitcoin will start working for you by generating more profit as the price of bitcoin is increasing with timeline, and your bitcoin investment will start be your pride and it will take care of your expenses and whatever you need money for in your old age.
Your illustration is quite alright but I want to ask you from your illustration what if at the point of the parents taking care of the child in other for them to grow up and take their own responsibility then peradventure the parents losses such a child while they are trying to grow up is it a gain or a lost to the parents? See everything we are doing in life is just risk as no one knows exactly what the future holds or how it might turn out to be so also is our investments as we invest not actually because we are certain that we will make profits but because of our optimism towards positivity so anything is expected to happen to ones investment be it on the short run or the long run.