You are the norm in that you seem to be communication-averse. Technical staff don't make purchasing decisions anyway.
Not OP, but I worked for years as a telemarketer as a teenager, so I'm not afraid of speaking on the telephone. However, as I've aged I've found that I'm extraordinarily bad at thinking on my feet and it is for this reason that I loathe telephone calls now.
I was raised to be a people-pleaser and no matter how many times I read "When I say no, I feel guilty" my gut instinct during conversations in which I have to think on my feet is to do whatever is necessary to avoid conflict with the person with whom I'm speaking. With e-mail and other asynchronous communication methods, this is not the case for me as I have the time to craft the gentle-no or the push-back or to properly word the uncomfortable question.
Since getting married, I've gained an additional great excuse: 'I just need to check with my wife about this important decision.'
Tip for unmarried people: You can still use the trick above, no one would know or even care :)
The stress and all the negatives people are posting about here is the point.
Before you demonize any company doing this... Know just about every company with a product has a sales team of some kind and they are all operating with similar models. You are being annoyed by some sales people while the sales people at your company are annoying someone else.
But you're right that non-technical managers seem to love that stuff
That isn't true at all, at least not at all companies. And even when the final decision isn't made by technical staff, technical staff often have an influence on the decision unless the procurement process is particularly dysfunctional.
The human on the other end is an experienced, well-paid, highly incentivized sales specialist, whose job is, to put it bluntly, to screw you over as much as they possibly can. Talking to them means entering negotiations on their terms. Unless you're well-versed in dealing with salespeople, they will play you like a fiddle. The business of their company relies on clients clueless enough, or big enough to not be sensitive to losses at this scale. It's plain stupid to engage from a severely disadvantaged position if you have any alternative available.
This applies doubly if they're cold-calling you. They are the hunter searching for easy marks. You are caught by surprise and entirely unprepared for the confrontation. The right thing to do is to stay quiet and let them go chase someone else.
But in general I would say, both can generate misunderstandings, but lets say mail is easier to settle down.