That was my point. The turnouts come with metal frogs, but the frogs are dead and it's up to you to power it (usually with a switching mechanism somehow linked to the turnout).
The crossings could be the same. Make the frog metal, and make it isolated from the rails so there is no short,
and leave it up to me to power it.
But making it plastic dooms me to a dead frog no matter what I do.