Why aren't more cameras and lenses weather sealed?

So you decide you want to go to out to do some street photography. You look out your window; it's nice and sunny. You get dressed, prepare your camera gear, and travel to your destination.

No sooner you arrive: surprise! Isolated thunderstorms. It's the second coming of the divine deluge. Time to put your gear away and wait for the rain to finish, or perhaps just head back home.

I've been caught in this scenario too many times. You may ask why I did't bother to check the weather before leaving, but I believe it more exigent to discuss why I should even have to in the first place. We have consumer cameras that can focus as quickly as our eyes can discern, record cinema-quality video, and even see in the dark. So why are so few of them capable of handling a few splashes of water? I'm not a product engineer, but from my understanding most weather protection doesn't necessitate much more than a few well placed rubber o-rings and gaskets. That's not exactly breakthrough technology.

The solution to all our problems
via info.parcoinc.com

There are obviously ways around this. I can buy a rain sleeve, use an umbrella, or heck just go and get myself a 1DX and truckload of L lenses. But again, I shouldn't have to. This seems to be particularly pertinent as related to the advent of compact system cameras--DSLR quality cameras that are small enough to be taken basically everywhere. Indeed, I don't leave my house without my camera. And yet "everywhere" does not seem equate to "anytime".

Weather-sealing comes quite in handy during Holi
via sphotos-b.xx.fbcdn.net

This is precisely what led me to buy the Olympus OM-D E-M5(that name is much too long), the first weather sealed CSC. It and its sealed kit lens have served me well during many a rainy day. Yet as of this writing out of almost 40 other available native lenses, only 3 of them have any protection against the elements at all(and two of them cost well over a grand). I also recognize that weather-protected doesn't mean weatherproof and that I can only push my luck so far, but it seems baffling I can't use any of the other wonderful glass in a drizzle without worrying about damaging hundreds or thousands of dollars in equipment. And none of the other CSC systems has any weather sealed products at all.

Arguably the best lens available for Micro Four Thirds. $900 of useless in the rain.
via ppdrompin.net23.net

Maybe I'm just getting caught up in a relatively minor issue, but I feel like when so much effort is put into allowing us to shoot in more and more extreme situations, it's puzzling rain is generally not one of them. Newer cameras and lenses are allowing us to take better pictures at night and of quicker moving objects, but just as much beauty occurs during adverse weather conditions. Just as much life occurs on the streets during a rain, just as much children play in the snow, and hey, I should be able to shoot in a sandstorm if I want to. It's a shame we can't capture these moments more often.

What are your thoughts? Do you shoot in adverse weather often, and if so, how do you deal with such scenarios?

P.S. Lest I forget our foremost "everywhere" cameras, all our cellphones should be weather sealed too. Seriously.