Upgrade subsidy?
Yeah like where Orange offers 'subsidies' on upgrades that are vastly more expensive than those who just get a new contract and hardly different from buying the phone outright, and you still get a locked down phone!
Sim-only deals are pretty good if they offer all the features. Problem is people like Orange (maybe others?) will deny you from using things like 3G and TV services on monthly contracts unless you buy their own branded phones (because they won't issue 3G sims or provide the content for the phone for these services).
Though things are shifting now in the premium phone markets where consumers are now potentially better off buying unbranded sim-free phones which are not crippled or locked, or keeping their existing phone if it's expensive and only a few years old instead of upgrading. More so if you're a user more into smartphone features (PDA stuff), some data use and limited calls so don't need an expensive monthly tariff just to get a "free"* phone.
* - as anyone should know, nothing in life is really free. Too many people are suckers for this with mobile deals though.