Not true at all -- properties can definitely be VERY profitable
I think you're much better off spending all your money on getting to the next quest level versus spending money on property. The rate of return for the amount of time is so much greater if you spend your time on quests. In other words, you can earn much more money if you spend your time only on quests. Fights and real estate don't pay. Thoughts?
It's true only for a short time at the beginning of the game. But even then, as you progress properties begin to payoff so much more than the others that being anything other than a Mogul is a complete waste.
For the beginning of the game put all your points to energy. Keep doing this until you have 96 energy, which works out to about level 29. That way you'll have a full 8 hours of energy, so you don't waste any while sleeping. The energy comes back at 5 minutes per point, so 8 hours divide by 5 minutes is 96.
Next thing you need to know: never use the bank. Let me repeat: NEVER USE THE BANK. If you have money left over just put it into buying properties.
The way to buy properties is simple: just do basic math. The more of a property you have, the more it costs to buy, so if you can save up and buy bulk, but that's not _that_ important. You just want to focus on increasing your hourly income.
So, say you have 6 million bucks. You could buy a Luxury Estate for 5 million, which makes 50k per hour, or you could buy 2 strip malls for 4 million, which will make you 50k. Clearly you want to buy the strip malls. Basically you just keep buying the item that has the best cost / earning ratio, until something else becomes more profitable (because the price inceases as you buy more).
You can fight others, but you only steal 10 percent of what they hold, which usually isn't going to be more than 50-500k per fight.
Right now, I have 96 energy, so every 8 hours I do 3 and bit Smuggling by Sea jobs which makes 450-800k per job. So that's about 6 million a day (rough average). My hourly income with properties is currently 750k per hour, which is 18 million.
So as you can see properties vastly outweight jobs, which vastly outweighs fights. I'd like to hear from a high level Brawler, maybe I'm wrong -- I just know I never hold enough money to let others make a decent profit from beating me up, but maybe I'm in the minority?
I also consider myself to still be a n00b at the game... I'm only level 30, and feel I'm just scratching the surface of what the game has to offer.