Indeed. The counter argument, however, is the suggestion that Jane's higher returns are at least partially due to her ability to extract favours from the government. Perhaps her mis-managed bank was shored up in a crash, while Jo's better managed construction business went bankrupt.

Now, some heretics might suggest that it's better to stop the government doing people favours, instead of semi-blindly taxing Jane's gains for Jo's benefit and hoping most of it came from government favours (never mind that Jo is now extracting a kind of favour from the government herself), but such ideas don't get a lot purchase.