>>69827320After Cover, Youtube, and Taxes she's probably only taking home 20% of the total revenue. Even with extras like merch sales, any pay from UMG, and royalties; you're still not looking at a ton of liquid cash.
You also have to consider that she's bought a house in the states, buys her own equipment, pays for software licenses, etc. Being a musician, even if you're just a vocalist, is expensive.
She is still probably sitting comfortably in the 6 digit figures between cash and assets. That's not including things like the length of her contract with Cover or UMG, or any savings / investments she has made. When you're setting up long term financials you usually have long term investments that are not going to pay out for 30 years but have steady 5-10% growth. These type of investment are usually not single pay-in types either, and actually have you depositing fixed amounts at semi-regular intervals (every 3, 6 or 12 months.)
Cashflow is also an important consideration. Let's say she's pulling in 16k per month with expenditures in the 6k range. That's 10k a month of discretionary income. Without any other spending you'd still be sitting on 2 years of consistent income to hit the 1 million mark. We all know that none of us just pay bills and do nothing else so that factors in as well.