Why Buffett expects Japanese companies to give him, a passive shareholder, returns better than any decent US company is beyond me.

To summarize the heart of the problem, it's not so much that ex-US firms don't make enough money, but that the money doesn't end up in the pockets of minority shareholders for one reason or another.
Diversion through self-dealing restructurings (S Korea, France), or simply stacking up the banknotes in the corner (Japan), or any other number of ruses.

So I think perhaps Mr Buffett has had the same thought I have had from time to time:
If it's outside the US, insist on a substantial dividend. The sogo shosha have yields in the 3-5% range.
At least in that case you know that you're getting SOME of the profits. The disposition (or diversion) of the retained earnings isn't a critical factor.
If the dividend yield alone is a perpetual bond with a high and effectively inflation protected yield, you're good to go.
If, like Berkshire, that's what suits your portfolio. And, like Berkshire, you aren't counting on selling at a higher price in order to make your money.

For advanced students, make sure you're relying on the dividend from the same member of the corporate group that the controlling family relies on for spending money.

Jim