Taking profit from your Bitcoin investment is not something bad and worth debating since all purpose of investment is basically to get profit at the very end of investing. During this profit taking one should understand a simple terminology like this one, firstly who holds longer makes the best profits, then why collect profits too early if your goal as an investor is to make steady profits with your investment, taking some profits after separate cycles is not bad as per if the need for it occurs.
I disagree with the idea that whoever holds bitcoin longer takes the highest profit; instead, whoever holds the most bitcoin takes the highest profit. Even a short term investor can make good profits if what he has in his portfolio is greater than the number of bitcoins a long-term investor has. I would rather say expecting a huge profit should depend on the amount of bitcoin you have been accumulating during your buying stage if someone has to seel. This is because even if you hold 100$ of bitcoin for 5 years, don't expect to see 30k$ dollars in profit. On the other hand, if you have been able to invest up to a whole bitcoin in two weeks, within 5 years, i am certain that you may see at least 100x of bitcoin reaching 100k of which your profit is about $50k plus.
This is why I don't agree with the fact that people should sell if they have not bought enough bitcoin to expect a high profit. Some people are just propelled to sell because people are talking about selling. Don't forget that these people who have been preaching about selling may have bought almost 1 bitcoin or more in their portfolio and they still have the money to buy more, but you are still struggling to even accumulate up to 10k bitcoin yet you want to join the train to sell.
Of course you are right, the size of your portfolio will determine what you get as profit. Long term profitability is for people who has enough bitcoin already accumulated. It's just like the saying goes, that the future belong to those who are prepared for it. Everybody is shouting bullrun, but not everyone will profit from it. Some people already started preparing for the upcoming bullrun 2 to 3 years ago and they have their bag well equipped, whereas some people who started their bitcoin journey 2 months or 3 months ago are also shouting bullrun and they will follow those who has been preparing for long and sell the little they have accumulated. If you're haven't been accumulating for more than 2 years minimum, you have no business talking about selling part of your bitcoin. Don't sell if you haven't accumulated enough.