Why has the mountain west never been a Democratic stronghold?

[Scam of God]

And this predates the liberalization of the Democratic Party by a very long time - even back when the Republicans were the more progressive of the two, the landlocked west voted for the GOP in numbers about the same as they do today, so I don't believe ideology has much of anything to do with it. It is probably the only region of the nation that has never consistently voted for the Democratic Party over an extended period of time.

[Scam of God]

Though I suppose it depends what you mean by "an extended period of time".

I'd say that a generation - twenty five years, or five election cycles - would be sufficient. Roosevelt never made great inroads in the region, and usually won by only a few points in most states; he never dominated there the way he did in most of the rest of the country.