That was my point initially: -Forcing- it on people won't work. Changing it, and people would'nt accept, unless there was a DAMN good reason to. People would only accept it if there was a concensus that such a change was necessary. I can't forsee such thing happening now, but in 50 years, if Bitcoin gets mainstream, it could very well happen. Economists have no damn idea of how a deflationnary economy works. I may very well be that it can't work. And if it turns out to be the case, then bitcoin will have to change, or die.
Getting a consensus on any non controversial issue in a large group is nearly impossible. This is why there are no governments (beyond maybe tribe level) which work on consensus.
All you can do is fork the blockchain, you can't prevent 100% of the people on the planet from using the original. So it is more probable that there is a hard fork and people choose sides than the entire human race reaches a consensus on an issue.
Some outcomes that may occur:
The blockchain is forked and the new fork is supported by only a tiny minority. A super majority continue to use the existing fork. The new fork fails to generate the critical mass necessary and eventually dies off, is abandoned, or is attacked. The same thing can happen to the old fork is the roles are reversed.
The blockchain is forked and the new fork is supported a small but self sufficient minority. The new co-exists along side the old fork but never becomes as large or as widely accepted as the original. Due to the confusion of both forks calling themselves "Bitcoin" it is very likely the minority fork will be forced to adopt a different name. Once again the same thing can happen to the old fork is the roles are reversed.
The blockchain is forked and the new fork is supported by roughly half of users. Neither fork is willing to give ground and both continue to call themselves "Bitcoin". This creates mass confusion as there are now two mutually incompatible "Bitcoins". Human nature being what it is, members of each fork attempt to attack the other fork, exploit flaws, spread FUD to discredit it. The fragmentation of user support combined with the attacks and confusion of having two incompatible networks both claiming to be "Bitcoin" eventually kills the project. Bitcoin (both "Bitcoins") eventually die off and the best we can hope for is another crypto-currency becomes the new defacto standard.
The inertia will always be with the original fork. To remain on the original fork you don't need to do anything. To join the new fork requires change. Obviously the third scenario would be a worst case scenario. It is for this reason many Bitcoin users are pragmatic and will not support hard forks that are controversial because there never will be a consensus. It is better to work with what we got then let perfect be the enemy of good.
Now maybe many would not change, but the side with economic majority would win, because those who refuse the change would see their coin become useless if most merchants prefer the "newcoins".
That is a misconception by default at the point of the fork all users would have "coins" on both networks. If newcoin is adopted and oldcoin becomes worthless then the user hasn't lost any coins. However what if the disruption undermines confidence in the network and you see the value of both coins falls, merchant support wane, and exchange rates plummet. While you may still have the same number of "coins" it is entirely possible that the value (in terms of purchasing power) of your oldcoins + newcoins is less than the value of your current coins.