I disagree. Tractors do not stop or corner nearly as well as a lorry. I have driven thousands of miles in both. Including some very high end well set up agri setups.
A lorry is far far superior. Not to mention if you try to even remotely run legit the tractor ends up to light and being shunted around by the trailer. Fastraks are the only tractors with air breaks. Everything else is still on hydraulic. So when coupled to an air breaked trailer the breaks don't match. This is particularly bad with new Hollands as they only have a single break disk per side up to about 170hp and only two after that. Most tractors still don't have front breaks.
Even driven sensibly tractors simply handle terribly in comparison to tractors. What's more unless you run road tyres on them which is very rare. Cleated tyres have nowhere near the grip of a lorry tyre. Both pulling away and breaking.
I fear your comparing apples and oranges.
If you expect any tractor to match a lorry on a southbound run down the A38 your going to be saddened.
However Autumn, on A, B and Unclassified local roads will soon show why a tractor can without doubt be a better tool..... wet leaves and lorry's don't go together and the last mile into a job is normally where the incidents will stack up.
FYI to run a Fastrac properly, as with a Unimog you need to be running a either a Tandem balanced suspended trailer like a lorry would tow, or a dolly trailer. About the only time I've ever seen this done is the water board units which where soon phased out when the tachograph/O license requirement was enforced. Which was a pity as now they use 8 leg hooklifts which do nothing but drag mud onto the road, get stuck and quite often wind up in capers.
Regarding tractors not having front brakes, I can't remember the particular limits, but I believe up to 40K is acceptable to run using the front 4wd shaft and braking via that. From memory despite there being no issues selling and using tractors at 50K or more there is no enforcement..... which is another problem entirely. So to say they have no front brakes isn't really right. The more serious reality is if your using brakes rather than gears for downhill speed reduction you want beating...... FYI same with a lorry and I stand by my opinion that testing people in automatic lorrys contributed to the Bath accident.
In Europe, tractors haul loads exceeding that of the legal weight in the UK safely, with turntable/Nil drawbar weight cart type trailers being quite normal. It works because the trailer brakes work and the tractors are almost always correctly ballasted with either wheel weights, or water ballast in the tyres.
Regarding Cleated tyres.... Depends on the PSI run at and widths, but my money would easily be on the fact that a tractor tyre should be pushing near the same surface area as a lorry tyre considering most are the width of a set of dual wheels and feature a much larger radius than a lorry tyre..... the trailer where the braking force should primarily be coming from tend to be HGV spec tyres on trailers (NOT IMPLEMENTS) so there is no difference there.
Local countryside work where neither vehicle is likely to consistently top 30mph.... tbh the tractor has other safety benefits (like being able to drive off the road to unload rather than in the carriageway) more tractive effort when required and the ability to change body types.
It all depends on the attitude and ability to spec the right tool...... But mostly tractors are disadvantaged due to a archaic and badly understood/enforced licensing system.