I had a 2013 RAM 2500 Tradesman CC SB diesel that had 125k on it. My 2013 still had leaf springs and 500 pounds more rating than most 2500 diesels after 2014. When I weighed truck and current trailer, I was at 90% rated capacity for that truck. It always towed fine, and if we were not considering a newer, heavier camper, I would have stayed with it.
When I was shopping for 3500, the SRW only added 1400 ish for capacity. The DRW about doubled it. We are looking for a newer camper that suits our needs. We have cash ready to buy. With the current market, we are waiting. What has happened to us several times in the past is that we suddenly find something that is what we want at a great price for some reason, and we buy it. We did not want to be truck limited should a 18k+ camper be found for us. So my 2020 RAM 3500 Tradesman CC LB DRW HO Aisin (nicely equipped w/upgrades) has all the capacity I would need for any camper we'd consider. Any camper over 20k, and most over 18k, are too long for where we go.
So my 3500 positions me to take advantage of any options that open up for us.
One thing I did not plan on is being asked to move trailers on the weekend. A couple campers, but mostly equipment trailers. Pays well for a side job.