Players picked different president and president changed some settings, I think taxes before with law firm were below 100%, 99% and some cities were making 1% of their base income thanks to that. Still there is a plenty of room for taxes changes, and with lower taxes, cities with higher base income and cards reducing taxes will increase threshold for top400. Some of them might be completely inactive still if they have 1000 base income and tax for them is 99%, it makes 10 final income.