It isn't unlikely, it is just a kind of diminishing returns investment. I look at it this way, with a careful selection of components you can have a complete, stock appearing, suspension system that gets 95% of the performance you want for a couple of grand. When I say system, I mean front and back. For three times that amount of money you get get to 98% performance with any of of several aftermarket set ups. For five times that money you can to the 99% range.
Now, that isn't to say that it makes no sense to go with an aftermarket suspension, just that you have to decide what is important to you and how you want to use it. For some, the ability to adjust the car up and down while manipulating wheel rates means they can justify the cost of an air bag system. For some the WOW!!! factor of the best thing available is important. For others, the value per dollar spent is important.
With the air system you can always alter preload to adjust traction and alter mounting points to optimize geometry. After that, adjustments can be easily changed. However, with adjustable shackles, adjustable hangers, adjustable shocks, some spring clamps and some track time, you can also dial in the stock leaf springs to perform very capably if not better with no major alterations. It comes down to personal preference.
But, remember this is just my opinion. Others here will disagree with me and they are some what right or there wouldn't be such a growing aftermarket suspension business. I'm just old school that way. Besides, I love the shock factor of kicking booty with what is an otherwise stock looking set up that is dialed in to the teeth.
BTW, have you read the mopar chassis manual on suspension tuning? Might be worth picking up.
