Balance can be done very easily and over time it will continue to balance itself, just take IRL monthly taxes/expenses and apply them to hourly taxes/deductions in game.
Things like Car Insurance, Health Insurance, House/Property Tax, Utility Cost, if implemented into the server correctly, can solve problems like criminals who make 1k an hour owning countless supercars, or rich players owning all the most desirable houses and businesses.
Just a rough idea of how this could work:
Car Insurance - Scrap the unrealistic car insurance approach where you only pay for your insurance if your car blows up. With the current system, players who don't blow up their cars could potentially not pay even a single dollar for car insurance. Not sure what system this was modeled after but a system that reflects real life car insurance could bring about balance to a big problem.
Suggestion: Make car insurance an hourly deduction from your bank account based on a percentage of the cars total value. As long as you keep up with your payments, taking the car out of Mors should be free since you pay in advance. This is sure to stop people from driving super cars if they're not in the position to afford the insurance payments and cause them make more realistic decisions when choosing a car as a daily driver. It would also work as a money sink, which the server needs. Make it optional to have and punishable for not having if caught on public streets without it. Could even go the extra step as to jack up insurance cost for each accident or point/infraction on your license, forcing people to maybe drive a little more realistically. Say I want to own a supercar or dirt bike, but only for race track use, I have the option to not insure it but would be require to tow/flatbed it to the track when I would like to use it or risk fines, points, and jail time driving it there myself.
Health Insurance - Currently there is none, I could die 100 times and it doesn't really cost me anything.
Suggestion: Make health insurance an optional hourly deduction from your bank account. Factor in whatever number you like, but make a hospital visit cost something more to those who don't pay hourly for health insurance compared to those who do own health insurance. It's a smaller money sink, but it will add up with the rest, achieving a more balanced economy and less people owning things that they realistically can't afford.
Property Tax - Currently there is none. Rich players can buy expensive houses and that's it, its theirs forever, no matter if they lose their job or whatever the case may be. Not to mention, they can own multiple houses without it putting a single dent on their income. There's nothing stopping the rich people from owning more than one house or business/property and a simple property tax could fix that.
Suggestion: Make property tax an hourly deduction from your bank account based on a percentage of the house or property's total value. This will stop the rich people from owning every desirable property, business, house, etc. It will open up the market for new owners. It will give players with less, a chance. It will give the rich players the option to still own the property's but maybe think twice on being "greedy" and owning more than they need. Even more-so, it will give the millionaires with million dollar mansions, something to spend all their millions on. A house purchase shouldn't end at the purchase itself, there should be some sort of reoccurring payment.
Just those few examples could completely change the economy, as well as the mindsets of the players when choosing how they invest their money. There's plenty of money going out to the people of the city but not enough of it coming back. Not enough money sinks. Nothing to stop me from owning 10 supercars and 3 mansions working as a garbage man, aside from the initial money required to make the purchases themselves. Criminals making 1k an hour would stop driving supercars, because even though they could perhaps afford it initially, they just wouldn't be able to afford it "monthly".
And just my two cents.. there will ALWAYS be a gap in wealth between old/new players. Don't do the loyal players dirty like that, as its the loyal players who keep the server relevant.
I only spit out a few ideas, and I'm sure with some more brainstorming we could come up with more ideas to help balance the economy.
A wipe may temporarily solve the issue until it's an issue again.