That's not quite the right conclusion to walk away with. An iPhone could have a terabyte of RAM, and the "trick" that iOS uses to boost javascript performance in Safari would still be just as beneficial.And this is what happens when you put anemic levels of RAM in your devices...
In any computer, the amount of RAM and the performance of the system are completely unrelated until you reach the point where the system needs more RAM. Extra [unused] RAM doesn't do anything (which is why modern OSes have started trying to make use of unused RAM by leaving stuff cached in it).