I know several of those old ladies! I also know several JK, JH, Grand Cherokee, Tacoma and 4Runner owners that never go off road. Here's some math ...
Jeep Cherokee KL
That's 777,037 KL vehicle sales (not counting Europe or Australia). I read somewhere in the Toledo News that Jeep made 900K+ before moving the production line to IL for the 2018 model. Based on what I see on the road, let's say 10% are TH. Of those 77K TH owners let's say only 50% go off-road and only 25% are interested in modifications. That leaves about 20,000 after market buyers.
Granted it's a small population, but what if you could sell just $100 to each owner each year? That's a $2M business! I'm not an entrepreneur, but it would appear to me that the KL market is definitely ripe. JM2CW because I know I'm preaching to the choir.
The problem is in your market justification... If there were really 20k interested there would likely be more active users here... The shops I talk to feel the percentages are much more like 10-12% will ever go off road at all. Of those, many will take on (slight) damage and never go again or have so much fun they start to look to other platforms that will take them further. Being optimistic that 50% of those that go off road are looking for more out of their KL you still have to so some reduction for market share (there will be competition in any market). The bottom line is that I know the owners of three shops that did fairly extensive market research and they didn't feel there was enough to warrant the expenses in bringing much of anything market. Remember, they have R&D, engineering, equipment, and manning costs to offset. You also have to consider that a $100 item will usually only yield 18-35% margin. So that $2M really looks like $400k to most manufacturers.
Given that this is an income over 5.5 years you are looking at $~72k a year (before taxes and insurance)....
I'm not saying it isn't still worth it to some, but not the big guys. The KL seems destined to either be a DIY rig, or supported by small mom & pop type shops.
...not to rain on the day further, but the JL Wrangler is set to be released soon. Every manufacturer and shop is in limbo waiting to pounce on that vehicle, and the JT (Jeep Truck that will follow shortly after).