How do you think Industry standards are created?
A bunch of companies says "Hey everybody, use my thing". One company wins.
Just look at BluRay Vs HDDVD.
In this case though, the SIM format is agreed by practically every major telecommunications operator in the world, so there aren't really any competing standards. That is, Apple don't have one SIM format and Samsung another. They sit down and agree on a single format, and that's the only one that appears on the market.
In this way, the SIM format follows a universally agreed and natural progression, rather than survival of the fittest, because this is the most cost-effective method.
Apple can really only be accused of forcing the standards to be agreed and implemented faster rather than forcing their own "standards" on everyone else.