You missed out some important steps you should undertake when creating a product, e.g. check that someone else has not invented something like you're doing first, just in case you might be infringing on their IP.
Apple clearly didn't do that step, or chose to ignore their findings if they did undertake it [or perhaps they just took it; wouldn't be the first time]. For the record Apple acknowledge infringment and the only argument has been what were reasonable royalties for the use of someone's else property.
As for why a jury gets to decide, well because both parties must have accepted that would be the mechanism and of course the jury would have been guided by the judge as to the limitations of their authority on the matter.
As hard as it appears for you to accept, the legal system works when you win and you lose; every case has one of each!
Almost no business checks for patents first. There are more than 10 million issued patents in the US. Many millions more world wide. Even putting aside expired patents, there are millions. And each patent can have dozens of different claims. It would easily cost millions of dollars to do an analysis of every patent that could have something to do with technology found in a product like the iPhone. And the end result would be six dozen patents that look pretty relevant. Then you’d have to determine whether the patents are valid (the ones in the virnetx case turned out not to be, by the way) which means you search for prior art which costs a lot more money. And outside lawyers then perform the analysis and draft formal opinion letters, which cost fifty thousand dollars per patent.
And if your lawyers tell you the patent that looked scary really isn’t a problem because it requires round corners, and you have diagonal corners, but a jury decides otherwise, then you now may have to pay triple monetary damages because you were already aware of the patent.
This process simply isn’t done. It would be insanity.
I mean, go to google.patents.com and try to tell me if the things you do all day infringe any patents. I guarantee you that you are infringing patents every day just by USING your devices, using the internet, etc. (The law says that you are infringing if you merely USE an infringing device).