(disclaimer: I'm not FI or retired yet)
From everything i've read about setting up investments for FIRE, most seem to agree that to live off dividend only (in a broad and balanced portfolio), you may need somewhere in the ballpark of 2x - 3x the stash that you would otherwise need if you were just using the 4% rule regardless of what the dividends were paying. If you specifically pick all high dividend stocks, you could reduce the amount you need back down to around 25x annual spending (the 4% rule amount), but might endure much larger fluctuations in income than most in FIRE here. Experts, please correct me if i'm mistaken.
I'm not correcting the spirit of your question, but will correct some of the numbers.
If you wanted to retire living just off dividends and were buying the S&P 500 index, you'd need ~52x annual spending to FIRE today (so about 2x what the 4% rule would suggest).
Getting to 3x what the 4% rule would suggest would require the stock market to run up another 50% without an dividend increases at all. The lack of increased dividends would likely imply no or negative earnings growth, which would mean a 50% increase in price would put us up at a Shiller PE ratio of 45 (comparable to the very last days of the internet stock bubble in 2000).
Now one way people approach deciding to live off of dividends is to pick companies (or index funds) that actually pay dividends (so no amazon, no google, no berkshire hathaway, etc), or specifically that pay higher dividends than the overall S&P yield, which includes a lot of those no dividend companies. If they do this in moderation they actually end up with a lot of low volatility companies in mature sectors of the economy (like electrical utilities), paying on the order of 3-3.5% dividends. The risk here is that these companies will almost certainly grow more slowly than the stock market as a whole (if at all), but they tend to also be respond less to overall swings in the stock market (lower beta), and their dividends are reasonably safe even in recessions (the electric bill is one of the last things people stop paying).*
However, you're certainly correct that if people start looking for even higher dividends, they start to get into very volatile waters, particularly since those high yields tend to be correlated with worries about the future of the company, and when/if those problems materialize, the dividend ends up cut, and it turns out the high yield was the only reason people were buying the stock at all. One of my handful of individual stock purchases was a company called "SeaDrill" because I was excited about how high its dividend yield was (stock price had just declined but I figured the yield was so good that even after a major cut in the dividend I'd still be okay). And well.. you can see how that worked out.
*In case it sounds like I'm making the case for retiring on dividends here, keep in mind you'd still need to save between 28.5-33.3x your annual expenses to retire on a portfolio of 3-3.5% dividend paying stocks.