Scotty -- I am sure you really meant some companies have been (as SDT said) leaving off DRAFT control on many models, not POSITION control.
ERROR MY MISTAKE; SDT did talk about Position Control being removed from many SCUTs. I back off and say I'm not aware of that stuff. My 30+year understanding is what I originally described below.
I have yet to ever see a tractor with an hydraulic 3pt hitch that did not have position control. I'd be curious what tractors are being made without position control (if you really meant that.)
Gary: None of the 3pt lift controls are made for "full up or full down" with nothing in between. At risk of offending the intel of many readers who know the what and why of Draft control, I'll comment as follows:
All (so far as I know) tractors provide Position Control which is the most simple and just means you raise or lower the 3pt as needed with a single lever. Nearly 100% are downward by gravity or implement force only, not hydraulics. As SDT said , Draft control is usually found on larger machines made to faciltate plowing and heavier tillage. In short, DRAFT Control requires sensing of the vertical load on the implement aft of the 3pt. [The one I have more experience with senses load on the top link though there are some that sense lift arms, etc.] That sensed vertical implement load is used in a feedback system internal to the tractor to reduce the hydraulic lift if the forces are above a threshold. On tractors with Draft Control that threshold is set by a second control lever. Typically that second (Draft) lever is kept in an "out of service" or "not in use" stored position effectively disabling Draft Control while the user operates the tractor using nothing but the Position Control. When you do invoke Draft control, the 2 levers both have an effect on the height of the implement. The Position lever sets the static level relative to the tractor while the Draft lever controls the dynamic level variation. While Draft Control might offer some protection when hitting a rock, the main purpose is to keep the plow a more constant depth in the ground and not have it riding up and down irregularly as your tractor rides up and down over the terrain.
Tractorrr: In your stated applications pulling drags, land leveling things, and even the tiller -- I doubt that Draft control would help you at all. I think of it as nothing but a confusion factor unless your are plowing.