'would have had to

Question

I found this passage from my reading book so it couldn't be wrong :D But I don't get it!

It used to be that if you wanted to watch a movie, you'd have to watch it from your television.

I think my below passage would be correct.

It used to be that if you wanted to watch a movie, you would have had to watch it on your television.

it's talking about past, right?

Answer 1

Use of the modals is tricky, because they have only two forms to cover a multitude of meanings. As a gross simplification:

If you wanted to watch that movie, you would have to ...

The sentence you quote exhibits a 'backshift' into past tense of a present-tense 'real' conditional, a conditional which represents your wanting to watch the movie as an actual possibility:

 If you want   to watch that movie (now)  you will  have to ...
        ↓ BACKSHIFT                           ↓ BACKSHIFT
 If you wanted to watch that movie (then) you would have to ...

But notice that the shifted version, with the past-tense verbforms, might actually represent a present-tense 'unreal' conditional: not a 'backshift' but what you might call a 'sideshift' onto a hypothetical alternative timeline which represents your wanting to watch the movie as nonfactual:

 If you wanted to watch that movie (now) you would have to ...

So you've used up your past verbforms to express unreality—how then do you 'backshift' this present-tense unreal utterance into past tense? It depends ... English syntax acknowledges two degrees of 'unreality', which we might call 'weak' and 'strong'.

• A 'weak' unreality is one regarded as possible but to some degree improbable: "In the unlikely event that you want to watch that movie". When this is backshifted into a past situation, the verbforms do not change: there's a 'null backshift' and you have to rely on context to supply the past time reference: If you wanted to watch that movie (now) you would have to ... ↓ ∅ BACKSHIFT ↓ ∅ BACKSHIFT If you wanted to watch that movie (then) you would have to ...

• A 'strong' unreality is one regarded as impossible, contrary to fact: "You don't want to watch that movie". When this is backshifted into a past situation the verbforms are cast in the perfect construction:

If you wanted to watch that movie (now) you would have to ... ↓ BACKSHIFT ↓ BACKSHIFT If you had wanted to watch that movie (then) you would have had to ...