Another concern is just where the labor is supposed to come from
The USA unemployment rate is currently below the long term average and they're planning for mass deportations.
What are they going to give up doing in order to restart basic manufacturing?
Is the primary that big of a deal? Given the limited time for campaigning it seems reasonable that the party appoints a candidate they can all get behind.
I don't really understand though - we don't have primaries here. We expect our politicians to exhibit the suitability for the role by convincing their colleagues to back them - kinda like they'll have to do in the wider government should they get elected. The parties just publish their lists of candidates (ranked) and we just vote for the party.