You can definitely buy more rugged phones. Often they lag behind in specs compared to popular flagship models, but they're not bad. For instance, I currently use a CAT S60 phone: http://www.catphones.com/en-gb/phones/s60-smartphone

After a normal day of use I'll still have 60% of battery life. It's normally water resistant down to 6 feet for 30 minutes, flipping two switches makes it water resistant down to 15 feet for 30 minutes (and it even comes with a "drying" app that helps it to dry faster by, I think, vibrating the speakers.)

This particular phone comes with FLIR imaging, which probably isn't useful to the general population...

That's fucking cool. Is that the same "CAT" that makes things like bulldozers and scoops?

It's the same CAT brand, yes, but the phone itself is developed by I think a British company.

Cool. If I had the money, that would totally be my next phone.

Not many phones do.

But a few have done what you suggest. At least slightly. The Galaxy s6 came in an active version that had like 30% more battery and better water resistance and a slightly tougher default shell.

I don't know how their sales were for the 2 models but I hope they were good enough to continue the trend

See the Samsung Rugby series.