You know what would be almost functionally equivalent. Release bitcoin2 as soon as it becomes a problem. it could be literally exactly the same as bitcoin1 in every way except 2. The market would drive people to adopt bitcoin 2 and 3 and 4 when transaction fees became unresonable, but they would also have incentive not to addopt too early since the more established chains would be more marketable...
Anon136, the problem is that while competing alt-currencies is perfectly acceptable within the cryptographic community, it would be a major pain to the public at large.
The public just want
The Bitcoin. They have no stomach for multiple variations, it would be like the VHS/Betamax or Blu-Ray/HD-DVD debacles all over again, but worse, bitcoin 1,2,3,4 would be the same kind of problem but on steroids!
If it can all be done in the background with multiple blockchains seamlessly integrated, invisible to the public so that there is only bitcoin - then great. But how soon can that kind of technical solution emerge? Not as quickly as saturated 1Mb blocks will happen.
And thats why, even if Bitcoin isn't the theoretically the best system for micropayments, it WILL be the system for micropayments. Betamax was technically superior to VHS, didn't matter, it lost. Alt currencies might be fine if you are a crypto nerd, but the public won't accept them. We are having enough of a challenge convincing ordinary people that Bitcoins are money. But when we do, they want them and they use them and THEY BECOME MORE VALUABLE.
Bitcoin's value comes from its function and trust. If it becomes expensive to use Bitcoins, the game is over.