People are able to get the most expensive car in a matter of days.
You can honestly grind for three things in this game: Cars, guns and firearms level.
Marksmanship was a fun grind too, although it was extremely pay-to-win and sucked.
I think there needs to be a fine balance between grinding and fun.
@StephenPuffs makes a good argument about car upkeep but honestly the 75EUR/month car tax i pay in real life pains me enough, needing to pay to upkeep my cars similar to GTA v doesn't bring any gameplay, it's just going to be as annoying as buying burgers and fueling up your car. In fact, it would make people grow more, since there would be a higher cost of living. You pay for something and you dont get anything in return: you just don't loose anything.
I dont think the 15 year old engine is helping out here. The amount of content and things to do is incredible for the engine, really. In terms of cool toys to own helicopters and boats on a garry's mod map are completely useless although an incredibly cool thing to grind for. Sadly, basically impossible. Some Arma RP players can relate. adding new things to own or making things more expensive wont fix anything. Making a 3 million dollar car 5 million will just mean some sweat skips an extra day of school to powergrow more. Having something besides cars to grind for would be amazing, but unrealistic right now.
HL2RP, despite having permabans on practically all servers in existence did teach me items aren't needed for roleplay. So, i think putting more focus on job immersion can do the trick for the economy. Drugs should either be an extremely high risk/high reward thing or should just pay less overal. Forcing people out of bases and into better paying jobs, even if it pays way less than growing. Will at a certain point interest them more in grinding for jobs than grinding for cars and drugs.
To round this up and to make my half drunk 3AM reply a little more clear: Having something to grind for isn't nessesarily a bad thing but people need a fair chance to grind for it. Sweaty McSweat shouldnt be able to buy his lamborghini by 2 days of growing because he is in a big org. Regardless of the price of this car, it will eventually be purchased by many and you have the same problem. Instead, you should be able to grind for certain jobs, improvements to jobs and similar things.
A server i used to play gave everyone access to the basic jobs, playing as this job(Say policefor example) gained you experience. At certain amounts, you would unlock advancements and some perks. At 1000XP, you get an upgrade to this job, a tazer and increased pay for example. Then at 2000XP, you gain something else. What these should be in perp, i don't know. But there definitely needs to be a few jobs where you have something to work for apart from policing, without adminstration behind it.
as an example:
a normal firefighter gets a small firetruck, a hose and extinguises stuff.
After, say, 25 hours on duty you get promoted. You get access to a firefighter SUV with small firefighting equipment allowing you to patrol. Ranking up further grants you better equipment, a better pay and a ladder truck. Progressing further grants you EMT capabilities or something, idk.
I dont know good examples for this, but i do think the idea of grinding for job perks instead of guns and cars will make people just grind less in general.
People will own that Lamborghini sooner or later. I don't think the economy is the issue itself, its just a consequence of the game mode revolving more about drugs, guns and raiding than ever before