Your Income will Increase by 50%

[DeadParrot]

Wealth isn't only spendable cash on hand. As the description of wealth mentions, the average middle class US American has more wealth then a King in the 1600s or 1700s. Not as much spendable cash, but far better standard of living. Most of us in the US can get in our personal carriages and in a few minutes be in a store with more food variety then that King could imagine. Or clothing options. We can use a device and after a bit of typing, send a message to someone almost anywhere in the world that can be received in a few moments. (Very useful when you remember that the Battle of New Orleans was fought after the Peace Treaty ending the War of 1812 was signed because the 'Wars over' message had not gotten there yet).
Not to mention having a wide assortment of 'court jesters' on beck and call using yet other devices. And you don't have to pay, house or feed them when they are not performing.

I can definitely see where a higher TL will result in a higher wealth level even if spendable cash doesn't increase.