Each bitcoin is currently divisible to 100,000,000 parts with the current software. If divisional granularity every became an issue the extra bit could be used to signal extended range.  This would be a simple, technical, and economically neutral change if it were ever required.

People who have invested resources and money into bitcoin did so with certain understanding and expectations of the dynamics of the system.  Your proposal would rob them of the expected return that was rationally factored into their decision.  Even if you'd benefit this time what reason would you have to expected that the _next_ change wouldn't rob you?   

There are some invariants in this system. Mess with them and you will completely and justifiably destroy all confidence in it. Other decisions are justifiable and are worth exploring but they should be explored in alternative systems (like beertokens) rather than by destroying this one and salting the earth for all similar systems.