Personally, I have my doubts that the mere fact that a person who presumptively has been in bitcoin longer and presumptively accumulated a decent amount of BTC at lower prices would not necessarily panic during various extreme BTC price dips.
Sure, there should be more systems in place that contribute towards longer time bitcoiners to figure out how to manage their bitcoin portfolio and other parts of their cashflow, yet I think that from time to time, some of the longer time bitcoiners do panic and make decently sized mistakes with some or all of their BTC holdings, yet many times, the longer term bitcoins will not be very likely to be playing around with large portions of their BTC holdings, so if they make mistakes, such mistakes would more likely involve less than majority portions of their BTC holdings rather than more than majority of their BTC holdings.
For a bitcoin holder that have held their portfolio for a long time, they must have gotten use to markets dips, up and and down and all of those panics that is being accompanied when bitcoin dips. For every time they experience that and are able to get of that zone without selling off, their minds becomes stronger and have a stronger will to hold for another when the market crashes again another time. Even when they are tempted to sell some parts of their holdings at that time, seeing how the market reverses later and they get back on profits again, they’ll learn a lesson not to sell at such times because whenever the market dips, it comes back to its form again. Having this experience will always reduce the tendency of them selling most of their holdings and rather sell a small portion of them.
I believe the longer a person has been HODLing, and the lower his/her average purchasing price - he/she would have less probability to panic. That's perhaps because of simple human psychology and experience?
Think of person who bought his/her Bitcoins last cycle with an average purchasing price of $5,000 vs. a person who bought his/her Bitcoins this cycle with an average price of $50,000.
The solution for people who panic - Cold Storage in an offline computer. It will take a few extra steps to move your Bitcoin, making you not to move them at all.

You are right though, but if you’ve met some people who panic a lot and are scared of losing money, they won’t care no matter the stress it’ll take them to take out their money when they see their savings already going into loss. Storing in a Cold storage in an offline computer is suppose to discourage them but at that point they won’t feel the stress and vigorous step to take away their savings. They can’t be a permanent solution to those who panic, they just have to make up their mind and work through their psychological mindset on how they react to markets when it dips. Some people will see those periods as another good buying opportunity for themselves only if they can and have reserve funds to grow their portfolio more in that period.