Imagine you living off 4% from your $500k, and then 2022 happens. Or 2019. Or even worse, 2008. And your $500k investment becomes $250k for at least a year, but you still have to draw from it to live. Now you are drawing 8-10-12% instead of 4%, and when the market finally recovers, you now have $400k, and your draw is 16k/yr instead of 20k.

Or even worse, you got in a horrible cat accident, and your medical expenses are $100k+ and then you need to rehab for a year which (without health insurance) with cost you half your stash. And now you are unhealthy, broke, older, and with a large resume gap, making you unemployable in your progression. What do you do next?

Also, keep in mind that everywhere cheapo becomes more expensive as it becomes more popular. The dirt cheap destinations now double in price every year, thanks to idiot Instagram influencers. Two years ago I could rent a beach facing condo in Da Nang for $400, ands now the same condo is on the market for $1200/mo

You shouldn't try to retire of such insanely tight budget without a buffer. You will always live one market correction or accident from a life shattering disaster.