I joined an AgTech firm 3 years ago - this is my commentary, not the view of my company or anyone else there.
> I actually assume farmers are very welcoming of technology.
The answer (at least in my experience) is a bit more complicated.
> Usually technology makes them more efficient and more money.
...because this sentence isn't really true.
Yes, farmers are hard workers and if they aren't adequate at business they fail, as the industry is....weird (high capital expenses, large variability that is outside your control). They also tend to be much older (it's not unusual to find a 60 year old farmer that is getting excited because their father is considering retirement and leaving them finally in charge of the farm). And they have been targeted for new technology long before the current data- and/or robotics- oriented trends, so they've heard plenty of grandiose claims that weren't matched by results.
Adopting a new technology is almost always pricey - either it applies to the field, so multiply the price by the acres and it gets quite large quite quickly, or you apply it to equipment, which tends to run $50K-$100K and have to last quite a few years)
Weather is the biggest variable in farm output, and it's both hard to measure and impossible to control, so knowing if a product works reliably requires testing in all sorts of weather conditions, which is VERY hard to arrange.
Trusting the benefits is also difficult - anything tested in Nebraska will find that Idaho is completely different - different soil, different weather patterns. Even if the product IS tested everywhere (and it isn't, not in sufficient detail and over sufficient time - remember that variability?) the farmers have been told that before - they'll want to see it, or see it from someone they trust to know their specific conditions.
Then there's the level of output. Look at GMO seeds - leaving aside any other controversy (for now), studies show they DO offer yield benefits, but whether that is enough to recoup the costs is a "that depends" kind of answer. When prices are low, the return value of yield is low, but the costs of whatever you used to increase yield is probably fixed.
When you add in the cost of adopting a new technology plus the low level of trustable benefits a healthy amount of skepticism is present. There's a reason most transactions occur between people with some level of established relationship - seed dealers, regional agronomists, etc. This means convincing a farmer is often a matter of convincing one or more of these other people first, THEN convincing the farmer.
My personal experiences found farmers more interested in adopting technology than I expected, but at the same time any limits that are encountered tend to be VERY hard limits. Until they've seen something recommended by someone they trust that is familiar with their local conditions, they won't risk a harvest on it, and even running a test strip of, say, 10 ft x 100ft is a non-trivial expense. So while they are more tech-adopting than I expected, and once they truly adopt something they tend to commit, they are not what most would consider "technology friendly" and have a respect for tradition and local relationships based on a history of significant financial pain when they defy it unwisely.