you can increase the load capacity just get XL rated tires, it's no different than putting higher load rating tires on a trailer for better towing
Tires don't magically increase your payload or tow rating. For most half-ton SUVs, the limiting factor is usually something other than the tires. For one, that weak-ass semifloater rear axle. Second, the crappy half-ton braking system.
On my 3/4-ton Suburban, the limiting factor on my rear axle weight rating is actually the tires. The axle itself is rated to 8600 lbs, but my RAWR is 5500 lbs. In other vehicles with the same axle, the RAWR is 6036 lbs, which is exactly 2x the 3018-lb load rating of a 245/75/16 E load tire.