Not sure I'd agree with the 4-runner being a leading sales champion among it's peers.

The Jeep Grand Cherokee, and Ford Explorer sell at a much higher volume. Though to be fair calling the Explorer and off-road vehicle is being very gracious to it. The Grand Cherokee, especially as say a Trailhawk is significantly more capable than the 4-runner. More clearance, much better angles.

2021 #'s
4-runner: 145,000. #24 best selling
Wrangler: 205,000. #15 best selling
Ford Explorer: 220,000. #14 best selling
Grand Cherokee: 265,000. #8 best selling

2022 so far (article from July numbers through Q2)
4-runner.....unknown but < 70,000 because it didn't even make the top 25.
Wrangler: 100,000. #15
Explorer: 103,000. $14
Grand Cherokee: 135,000. #6

I have to admit I've never been a Jeep fan, but it's shocking to me that they sell that many. I feel like I don't see that many Grand Cherokee's around. Making it into the top 10 consistently is huge considering 1/2 ton pickups dominate the top 3 every year and hold 4-5 of the top 10 spots. They are selling at almost 2:1 to the 4-runner.

I want to like the Gladiator but I can't, it's not enough pickup bed to be useful, and I'd rather just have enclosed interior space for cargo. Also, the rear is just super ugly to me, it's almost like two different designs from the cab forward and back. However I can see it's utility if you wanted something with an exposed bed and was super off-road capable, make a great dedicated hunting or ranch vehicle but these days a side x side will go more places than almost anything that's street legal. Also Jeep makes some really weird decisions, for example the Quadra-Drive system is great, but you can't get it on almost anything anymore, and what you can get it on has 20-21' rims.....hardly off road. The only trailhawk Grand Cherokee is now a 4xe. Same for the 35" package on the Wrangler, can't get it with the diesel engine option, and can't get it on the Gladiator at all.