Reporting to your phone company that the phone is stolen can take it out of service.
Many already have this ability, some telecoms are dragging their feet, that's what should be fixed.
The government doesn't want this for theft prevention, they want it for crowd control and to be able to target anybody they don't like.
Since you can already get apps on both Android and IOS that effectively find, track and also remotely erase your data on a 'lost' phone, I would have to say you do have a point. It can, and if implemented it probably will be used to do so. But that being said, I don't believe in the 'conspiracy' when bloated bureaucracy can explain most actions of government. Most laws are not put in place to protect people who are aware and proactive enough to protect themselves, they are put in place to protect the lazy from the unethical. It's the '10% of the population are jerks' tax we are paying with this law, and the telecoms are dragging their feet for two reasons, cost and difficulty of implementing change, both will effect their bottom line, which is their only real motivator. Additionally it might reduce the amount of phones that are sold.
I don't downvote opposing viewpoints, as they add to the discussion.