The journey of a thousand miles begins with a step and I consider those who were opportuned to mine Bitcoin and also invested at the early days as the ones who took the best step, it's not supposed to be debated cause we've all seen the success of the project from the first day of creation by Satoshi to this present day, except maybe the ones who sold their assets for unnecessary wants, but people who held for a long term are benefiting well from their decisions currently.
From my little experience, there is nothing wrong is selling but it is important to replenish your wallet when the price goes down. So the people who lost out of the benefit of Bitcoin are those who sold and didn't re-buy during the bear market. Bitcoin still has great potentials, so it is still okay to buy and hodl because the the price will appreciate in the future.
I wonder how many of those who invested early on actually managed to hold long enough. I joined only around 2015, and even I remember a time when $600 per BTC felt like such a great price. Apart from selling, it was easy to lose coins due to scams, locking yourself out of your wallet, or accidentally making transfer mistakes.
But no matter when someone invested, surely it was hard not to sell at some point. In the grand scheme of things, I agree it's not too late to invest, but people should do what feels right to them.
Those early Bitcoiners who kept their coins to date are superhumans. I might sound somehow but this is just how I see them. It is not easy to keep a worthless coin and if the price went high, they were not tempted to sell them. I don't if I had kept my coins to date, I would have sold them a long time ago.