I’m afraid, sp, that I do not share your optimism surrounding the “legacy” that the Games will leave.
It started long before the Games. The chaos caused by the ridiculous torch procession must have cost millions in lost business to companies all over the country. Quite a number of local businesses have already gone to the wall as a direct result of the chaos in East London and a number of others are expecting to do so. Many more have had to be relocated. Some of this makes interesting reading:
http://www.gamesmonitor.org.uk/
Of course in the current climate the security services will be in their element. No fly zones already in place; draconian parking restrictions already in place; vehicles to be prohibited in Westfield Shopping Centre for the duration and much, much more, all in the name of security but all of which will enable the police and others to bully people around. Still, look on the bright side: some residents who are on the "walking route" from Leyton Station to the stadium have been given a Grand each to tidy their front gardens.
Comparison with other smaller events is disingenuous. The Olympic chaos will last for months and will be widespread to a far greater degree than the other functions you mention.
The big winners, as always, will be the multi-nationals who are big enough to absorb the chaos and then make a nice few bob when all the mayhem has finished. The hope that the facilities provided for the Games will be long lasting is already crumbling. No agreement can be reached on the future of the main stadium short of tearing it down and rebuilding something else that others may be interested in. The equestrian facilities in Greenwich will be ripped up (and should never have been provided anyway because there were world class facilities in existence elsewhere). Exactly the same is true for the shooting facilities in Woolwich. Transport facilities should be developed for Londoners and tourists as a matter of course. There was no need to allow them to stagnate and only put money into them when the bid was won.
So no, I do not think it is even remotely worth it. Much of the Games will be tedious (after the eleventh heat of the Men’s 200m backstroke it does tend to become a little stale). Of course Londoners will muddle through; life (and death) will still go on. But the inconvenience and cost to most Londoners far outweigh any small benefits they might see. The vast majority of London Council Tax payers (who have paid a premium for the past six years to fund the Games) will gain absolutely nothing from them being held.
My Lord Coe is a master of hype but unfortunately suffers the delusion that everybody lives eats and sleeps sport as he seems to do. But if Londoners had been properly canvassed before the bid was made and their views considered and acted upon instead of them just being presented with a bill, things may have been very different.