Certainly true. Traction is also important. If it rained I let things dry out for at least a day, knowing it would be futile to try with slippery ground.I tried something like that with my BX2360 on my hill. About 2500 pound log on my 600 pound arch. Made it halfway up, had to use 4wd and all of a sudden started going uncontrollably backwards with the wheels spinning forward. Luckily a tree stopped me as everything was turning sideways. Takes weight to pull weight on a hill.
I use four-wheel-drive all the time myself since I don’t have any pavement.
The only time I had an experience like you described was on wet grass. Not fun. And I wasn’t pulling anything!