Keeping 4-5 years in cash is a lot of fiat hanging around.. .though there could likely be ways to do some variation of that, so it probably is not totally unreasonable.. to consider..

Let's say, for example, that a person had been in bitcoin since 2017 (using your forum registration date), and sure maybe he front loaded his investment, but let's say that he largely had put most of his investment into bitcoin over a couple of years.  Let's say that he put 2 years worth of his income, and so then his average cost per BTC might have had been around $10k or perhaps even less than $10k.. so maybe something like $8k per BTC.   

If his income was $50k, then that would have had ONLY gotten him around 12.5 BTC, so, from my perspective, not quite enough BTC to be able to stack away 4-5 years of fiat.  From my perspective, he would have had needed to get into bitcoin sooner..   Of course, if his average cost per BTC would have had been closer to $6k rather than $8k, then he would have had been able to get 16.67 BTC.. and he would be in a better place,  yet still I would consider that borderline to be taking out 4-5 years of fiat from that... .. not totally unreasonable but there does not seem to be enough of a cushion to cash out 4-5 years worth of fiat.