I wonder how stock options play into this. Assuming you have generous stock options in a thriving company, wouldn’t it be worth it to stick out 3-4 years for a majority of that equity?
With options, there's always a risk that they will be worth nothing, or very little. I would rather have some options in several companies than a lot of options in one to increase the chance that some of them will be valuable. That approach does require you to buy the options, whereas staying at one company means you can delay the purchase
If all the companies you work for have similar likelihood of doing exceptionally well, you've paid 4 years and gotten either one lottery ticket worth X (strategy 1) or 2-4 lottery tickets each worth 50%-25% of X. When you don't already have "enough" money, 25% of X is still life-changing, and if you can get 2-4 shots at it instead of 1, that can be a very workable strategy.