What environmental or biological factors would result in assassination being more common and more respected than soldiering?

Question

Essentially, I am imagining this scenario:

Somewhere there is a world where, in all the major civilizations, assassins are more numerous and more highly respected than soldiers. In such a world, wars as we know them virtually never happen, but attempts by high-ranking figures of opposing groups to have each other assassinated would be so common that they would have just as many assassins as we have soldiers. This would also carry over to how soldiers and assassins are perceived by the people of this world; the people would view assassins as fulfilling a regrettably unavoidable but highly honorable service to their nation, much as we view soldiers, while they would view soldiers, even those who operated in the strictest approval of their own government, with as much suspicion as we view assassins.

My question then is: How could this scenario happen?

I am imagining a scenario where this has been the case since prehistory, so technological reasons are out. I would prefer answers dealing with an effectively human society, so scenarios essentially featuring normal humans dropped into another world at the beginning of history are ideal, but it would also be perfectly acceptable to give a reason why the biology of a certain kind of sapient species would lead it to a preference for large-scale institutions of assassination over militaries as humans know them.

Answer 1

Island police state

Q: "people would view assassins as fulfilling a regrettably unavoidable but highly honorable service to their nation, much as we view soldiers, while they would view soldiers, even those who operated in the strictest approval of their own government, with as much suspicion as we view assassins. My question then is: How could this scenario happen?"

Island super power

Environmental aspect: your country is an island super power, with no foreign threads and no easy way to expand. The army exists and it has always been very powerful.. but it is not needed to serve the autocratic government's purposes anymore. The rest is political circumstances..

The enemy inside

Having numerous assassins in service of a government could happen in a police-state with growing opposition inside. The autocratic government can secretly issue secret murder assignments against any opponent. That can be inside the country, or abroad. The target are traitors, according to the government. There are lots of targets. So you'll need a lot of assassins. All people not agreeing with the government can be killed at will, without due process.

https://en.wikipedia.org/wiki/Police_state

Propaganda

.. and why is the army discredited? Well, as it often happens, the autocratic government is not supported by certain elements in the army, like generals and the ministry of defense. Propaganda will tell the people that these institutions are corrupt and need to be removed. The propaganda will tell people fake news, about officers plotting coups against the government. Soldiers become less respected. They are part of a public institution accused of treason. Side-effect of that propaganda is it will push more soldiers into the profession of assassin.

Answer 2

Physical incompetence.

Your world is a rich one. It does not take a lot of effort to get fed. In fact it takes much less effort than producing progeny, and it is the difficulties involved with latter act that limits your population.

The people are extremely sedentary. Even the minority that is not massively obese move only as much as is necessary to keep a modicum of distance between areas for eating and areas for expelling waste. Soldiering is hard work. It is not so much that it is dishonorable, but that really no-one can pull it off. Sustained physical activity of any sort, much less violence, is out of the question for nearly all of your populace.

Assassination is what remains. It does require exertion to get up, trundle (painfully) over to a sleeping person and light him or her on fire. Thus the honor bestowed on what passes for atheletes in your world.

And also it is for this reason that assassins are common. Anyone capable of this endeavor will do it every now and then as it is what passes for exercise.