In pak64 you need to wait ~5 minutes as the line pays for itself in 2-3 trips. In pak128 that is true.
It's an issue of balancing, but the current display of the bank account is useless either way.
* If the pakset is balanced in a way that money is growing on trees, you don't need to look at the bank account, you will always have enough money.
* If the pakset is balanced so vehicles are expensive, as stated, your bank account is irrelevant, you only care for net worth.
* If the pakset is balanced so vehicles are cheap but infrastructure is expensive so you can't make money easily, there is less difference between bank accound and net worth, and you can stay black without swimming in money. However, if you created such a pakset, you would want bankruptcy to come with negative cash, so the current situation would still be unsatisfying.
No matter how the balancing works exactly, as the player what you want to see is a value that, if it reaches zero, ends the game (liquidation is a loss, so the game still ends for the player in multiplayer) - not some value that is rather meaningless without further information.
The problem is that there are many mechanics missing from the game to make the bank balance make sense. Experimental is trying its best to add such mechanics however in standard there is currently no plans in that area. Basically if you had to pay interest on the balance, on top of vehicle value deflation, then it would make a lot more sense as being in the red will cost you and potentially eat away all your profits.
I disagree. There already is a meaningful value one can use to determine overall success and keep an eye on not to go bankrupt, the net worth. So the actual problem is that this meaningful value is not shown, but a meaningless value is. Changing which variable is displayed would already fix this.
Changing how money works in the game by adding some financial features might be nice to have, but not punishing ones. Eg. you can't just add taxes and make it so players have to give some of their income away. Instead, you reduce overall income in secret and add some aids and grants for 'poor' players, since positive features are better than negative ones and the overall impact is the same. But that's complicated and does not help making the game more accessible, so if you have concrete ideas please open an independent extension request.