The point is, theres no reason for the limitation, infact it cost them money and time that was completely unnecessary to implement in the first place.
The reason is that it keeps people from just leaving 100 pages open and then complaining that they can't find anything.
Ok, so you'd use it efficiently, but for every 1 of you there'd be 100 people who just don't close things because they're lazy. Then the iPhone would be known as "that phone where it's hard to find your tab."
I know so many people on both Macs and Windows who have a filing system of "I have 500 files on my desktop." Neither Apple or Microsoft can "fix" their legacy computers because people would complain if they changed them too much. So they're both stuck there, but they're trying to correct those mistakes in their tablet computers.
Trust me, those same people would make their phones into a similar a mess if they could. Apple's idea with iOS is that it would help people avoid that kind of crap. And it does that pretty well.
So removing this limitation would help you, but it would "hurt" 100 other users in exchange. That's a bad exchange for Apple.