I have this colleague of mine at workplace who is a bitcoin enthusiast just like me. Often times at work when we're less occupied with our job we kind of spend such moment's discussing about bitcoin generally. Two days ago he was telling me about his plans to start buying BTC with 20% of his salary every month for the rest of the years he has to retirement that's when he will then take it all. And based on the company total years of service he has 16 years left to his retirement.
I don't doubt the existence of Bitcoin in the next 16 years but if that 20% is the amount that he planned to use as retirement fund then I would suggest the diversification of that 20% among different assets and if he is not that much then atleast into gold so he may have something to not worry if Bitcoin is not expected grown. Or as you said taking out the profits after every cycle and invest them on other assets also good idea so it all comes down to our financial management skills.