You see, o Master Shit Talker, you are wrong.
I grew up on a farm, as I would think several others on this forum did. And we used mostly old Farmall and International tractors from the late 40's and early 50's. And the entire suspension on them consisted of a control arm that attached to the top of the transmission and had a spring and a shock underneath. The other end of the control arm ended in a flat metal pan seat. Every bump. Every woodchuck hole. Every frost heaved rock. Every up and every down was handed by this single control arm suspension system.
And when it was Summer an it was hay season I would use my Super H (IIRC 1952) to haybine, ted, and rake the hay prior to it getting baled.
That meant I went around each field, spiraling inward at 9' at a time.(we had a 9 food haybine) one day after another, after another. Obviously weather was warm, dry, and consistent for this.
One day while at Tempco picking up new mower blades and rake teeth for the upcoming season I noticed that they had stocked replacement seat springs that fit my Super H (among many other tractors. It was a standard seat suspension system at that time). They had both a light spring and a heavy spring on the shelf. Not knowing what was considered 'heavy' back then I bought both springs.
Upon returning home I was anxious to see if they would make a big difference in ride comfort (I use that word loosely here) or had I just wasted my money buying a pair of $20 springs.
As this is getting to be tediously long already, I can assure you that they did indeed produce very different ride quality. There was no other variable in this test. Same tractor driving the same speed (with a governor that's pretty easy) on the same place often on the same day, with the same weather, and the same shock absorber. The ONLY change was the choice of 3 different springs.
And having several tractors sporting the same suspension seat design I was able to see the effects on different tractors. Some had a longer control arm, some had shorter. Some had a better shock, some had worse. (My grandfather's W4 had its original 1940's shock still in place) Yet on every one I tried, changing the spring rate, and ONLY the spring rate, changed how soft or how firm that suspension felt.