[raverbashing]

> Feels like this is probably the result of telco networks wanting as much friction as possible to change providers

No, it is the opposite.

It is exactly done like this so you only need to get the sim card and not need to have the operator decide for you (of course people shoot themselves in the foot by signing a long term contract while getting a locked mobile phone)

[kalleboo]

I imagine one of the main reasons it was done like this was because when the GSM standard was designed, a non-insignificant number of phones were fixed mounted into cars (due to the sheer bulk), and then being able to bring your smartcard with you in your wallet and swap between phones (cars) would be a very handy feature.