Negating Plate Tectonics - Strike 5

Mission Impossible - Convection.

Plate Tectonics' story. Think about it.

1. A whirling mass of space dust, planetoids and planetisimals
gravitational coalesce in a cataclysm of impacts and heat generation.
2. The mass incandesces.
3. Using up the heat as it cools down, this mass differentiates and
forms a crust.

OK thus far? Y/N? So, ..

3. It's used up its heat to do that - make a crust and differentiate
it. It doesn't matter how many sources of heat remaining are intrisic
to the earth, there will not be enough left over to break the crust up
and destroy the products of convection. If there were, why would it
ever have formed a crust in the first place?

What's difficult about this? Surely this is common sense?

What convection-leg is plate tectonics standing on?

Count strike 5.