> they run out of ink quickly, they dry out quickly, the ink smudges until it dries, the ink will run or be erased if the paper gets wet, they are very sensitive to the quality of paper, they can leak easily in your pocket, etc.

Wut?

It sounds like you're talking more about dip pens than fountain pens? Because aside from the ink drying time (it does smudge for up to a minute for really thick lines), most of those are artifacts of older inks and pens. And there are a lot of varieties of inks to take care of fast drying or waterproofness, etc.

And a good cap will keep a pen from leaking in your pants.