Why do recruiters insist on phone calls for everything? Why can't they just send an email? I can't get on the phone while I'm at my job to talk to you about some other job.
Phone calls (or any form of live communication, really) are extremely efficient in comparison to email.
Email is pretty much the worst form of communication for most people. A conversation that would take 15 minutes on the phone might take weeks (if not months) to conclude over email, and because of that latency things frequently get forgotten or lost.
You might say: "Hey, if I don't respond to your email that means I'm not interested" or "This clearly isn't a priority for me, that's why it takes so long to respond" but on the other side you'll semi-frequently encounter people who actually are really interested but take a few follow-up emails to respond for whatever reason (busy, OOO, just forgot, etc).
Email is just very forgettable for most people, even for things that they might actually be interested in. You might be an exception. I'm a pretty strict Inbox Zero person, so I feel your pain. Still, you choose the tactic that works most effectively for the vast majority of people, and that's live communication of some kind.
Since I think having coffee with him is a total waste of my time, how do I even begin to think about a pre-call for the coffee?
Saying no is hard but we all need to learn to do it. If you're not interested, just say so.
If they are good, they'll lay out everything they want to cover and be upfront. Sometimes, this works well and I'll bite and accept the service or we will know right away it won't work.
The worst is when the person thinks they want to build a relationship first and hang out and talk about other things and then they'll tell me what they want to do. I simply won't give someone I just met some business just because (or if) I like them.
I agree about the business hours, almost none of us have our own offices anymore, so the business hour phone call should only be about making an appointment outside business hours when you can actually talk.
If you reply by phone it means you actually want a job.
Source: At a former job, I was work buddies with a guy from the in-house recruiting department, and he'd tell me stories about just how different his job there was from his previous job at one of those firms.
These recruiters sure they're not sitting on a local maxima?
You aren't going to encounter them nearly as often, though, precisely because they aren't just spamming indiscriminately. Also because there are fewer of them recruiting for fewer positions. The hiring company needs to be willing to pay for that level of service.