The key I believe lies within finding a balance based on the circumstances and position of the individual and their financial stability. I see that you also emphasized on the importance of having a discretionary income to invest in Bitcoin, rather than using money meant for other expenses, which would seem more like trading or gambling, and I see a lot of sense in what you've said, because if an investor forfeits his expenses and uses the money to invest in Bitcoin, it might later cause him some financial strain, and maybe even lead to using money from your investment to foot those bills/expenses.
Sometimes it can take a bit of time to put good systems and practices in place, and in the very beginning a guy might not even realize what is the difference between trading and investing, and even if he hears that others believe that bitcoin is a 4-10 year or longer investment, the idea might not sink in with him personally, so he might not actually understand it, even though he still might start out by investing into bitcoin with a shorter than 4 year timeline... but then as he learns more about bitcoin, he may well come to understand and accept that bitcoin investing is 4 years minimum for any of his new investments into it... and not a shorter timeline, so his ideas may well change as he better gets to know bitcoin and some of the ways that bitcoin is a relatively unique asset.
Yes expecialy the newbies who might have spent less than 1 to 4 months here. We have also been on that situation and needed a lot of conviction for it to sink into our head but as time goes it becomes part of us. And I believe why people finds it hard to understand the concept of 4-10 years or more, is because they are often stocked to the orientation of other people about Bitcoin investment and trading outside forum. A person who understands Bitcoin outside forum will usually have a different view about Bitcoin investment and trading but with the help of collective ideas from different people expecialy from thread like this will shape a person into another dimension of knowledge except such person is bent on following his own ideas. And I bet such person will never learn.