Modern rain gear is okay on that side but at great expense.

I ride like I'm getting paid for it, but that's just not really the case yet. Though it'll be amazing when some real innovation happens.

Even the highest end technical fabrics don't work very well when it's humid outside, which tends to happen a lot when it's raining.

If you're actually working hard, you'll be covered in your own sweat soon enough. Given the choice i usually just go with the rain instead.

Riding an ebike is a different matter, that's probably entirely doable with current tech.

What gear do you have? I use North Face futurelight and if I'm biking at reasonable to slower speeds I don't really sweat that much unless it's more than, say, 22C.