What if one spouse makes seven figures and the other is unemployed and takes care of the household? The income disparity then is too high for this, it seems to me, but maybe it's just me.
When money was tighter, we would coordinate more closely and more frequently about expenses and timing. Now I just maintain a certain balance in checking and we coordinate over large payments to make sure they don't hit checking all at once.
If you or your spouse is making seven figures, you shouldn't have actual money problems -- even if taxes take half, you can save half and still have 250k/year to spend; spend half of that on a $5M mortgage, and you've still got more spending money than US median income. Your money management priorities should be around limiting the time it takes to manage, unless you get enjoyment out of micro managing it.
Certainly when we made less money we had to coordinate much more.
Someone with a large income probably grew their income over several years (although, if you know of any career paths with seven figure starting salaries...), and have had a chance to learn that even though it's a huge amount of money, it's not infinite money. But if you do overspend one year, you're likely getting a bunch of money the next year, so you can probably work it out.
Or the outliers who blow all the money on silly things and make the news but aren’t actually at all representative?