Rubby, I have until recently done a 2 hour boil because that was how my first decent brewing book, Brew Your Own Real Ale at Home, (Graham Wheeler first edition) told me to do it. It is a simple as that. The beers worked so I saw no need to do any different. I have modified down to 90 mins. Now it may be that we have slightly better malt now and we don't get as much protein that perhaps needed the longer boil to precipitate out of the wort, though I doubt it. I have been brewing for 20 years using this sort of method with very few problems. The book is now at least 20 years out of date and thinking has changed it is not some silly desire it is how I learnt the game.