Wrong.
A voltage divider would waste just as much heat as a regulator. The main difference is that the regulator has a low output impedance. That is, the output voltage does not change very much if the load changes. Your voltage divider has a relatively high output impedance so that if the load resistance changes, the voltage will change.
A voltage divider will only work for low-current, very constant loads (like the base resistance of a transistor).