This is a pretty common “science fiction” scenario. Suppose you had a time machine. You go back in time, deposit $1 in a back, return to the present, and now you’re rich!
That isn’t what would actually happen. Suppose you actually went back in time 100 or 1000 years, and made a deposit, and traveled back to the present. What would have happened?
The inflation was more than interest paid, and you lost your deposit.
The government changed the law, nationalizing bank deposits.
The bank might have gone bankrupt, and you lost your deposit.
The government might have failed, and you lost your deposit.
The bank started charging more fees, and you lost your deposit.
There was a law that said the State can claim idle deposits, and they stole your deposit.
Even if you could go back in time and make a deposit, you would not made a profit. Even if you make several stops and withdraw at the right time, you still might not make much money.
That’s an interesting lie. “If you leave money in a bank or investment untouched, you will profit.” Money left in a bank account over time has *NEGATIVE* expectation. That would be an amusing “science fiction” story. Someone goes back in time, tries that trick, and fails miserably.