Actually in my own opinion this is a myopic idea, you can't just buy Bitcoin with the intention of holding and selling when it has gotten to it all time high, no you don't do that, how much do you think you might gain doing that, that can change your financial status forever?
So buying and selling for minimal gains is not the right way to go as a Bitcoin investor, or have you forgotten that we are still in the early days of Bitcoin, so it's nowhere near it peak price, and statistically, it has been proven that it's an asset that appreciate in value overtime, so just imagine what you stand's to gain if you can buy a huge stash of Bitcoin now at once or through the lumps sum method over the years and hold for like five circles, do you think that Bitcoin will still be at the $100k mark? No.
It would have skyrocket to a million dollar or more, so it's best you stop being myopic when thinking and talking about Bitcoin, because it's the real deal.
I understand what you are saying and I agree that buying Bitcoin just to sell it when it reaches its highest price might not be best plan. You are right Bitcoin value will probably go up over time and keeping it for long time could bring big rewards. If we look at what is happened in past Bitcoin value has kept going up over years so it is possible that its price could go over $1 million someday like you said. And I like which you said to think about long term and not just short term when investing in Bitcoin makes a lot of sense.