When code goes into production, all comments are automatically stripped out by various joiners, minifiers and uglyfiers. Production shouldn't have comments in it, but only because some sort of preprocessor like Webpack should be used to remove them.

Should there be comments in production code?

A handy rule of thumb is: a comment should only be added to answer a question that the code can't. If you aren't confused by what a piece of code is doing, but rather why it's doing it at that moment, then a comment should be added.

Should every line of code be commented?

Yes, it takes resources, but the payoff is better code. You will never be able to get the same bang for your buck by sacrificing comments for a better variable naming standard. Yes, commenting every line is nuts.