Are almost all states just going to eventually vote Democratic at some point?

[Skill and Chance]

No, of course not.  But if you assume Democrats get their 2012 percentages of each demographic that (minus ND, MT, AR, KY and WV) is basically what would happen in a ~55% white 2040 electorate.  The point is that something has to give.  In 2040, Republicans need to either win ~75% of the white vote or break even with Hispanics and Asians to prevail.  The nature of the 2 party system means that they will simply adjust their platform until one of those happens.  

[Skill and Chance]

Of course every state will vote Democratic at least once in this century, and vice versa as well.

How so?

Well, the 20th century involved 3 near 60/40 D landslides and 4 near 60/40 R landslides where they won about 40 states with somewhat different coalitions.  Just because 2000-2012 has been close doesn't mean the whole century will be.

[Skill and Chance]

Of course every state will vote Democratic at least once in this century, and vice versa as well.

How so?

Because every state was won by both parties at least once during the 20th century. The present order will die, though I have no idea what would take it's place.

Well it's not certain for every single state.  Vermont did have a 104 year R streak from 1856-1960.

[Skill and Chance]

For the two states most likely to have a >100 year streak going forward, I would lean toward Alabama and Maryland.  On the surface, Utah and Hawaii look like the best bets, but they both have idiosyncratic weaknesses (anti-Mormon gaffe/landslide reelection of incumbent R).  Rhode Island should eventually give out due to the elderly Catholic block there, but that might not happen until after 2050.