Simply not gunna happen.
There's a reason coin map only shows the location of physical shops that accept bitcoin and lite coin. Because these are the two original coins and even lite coin does not come close to bitcoin.
After a few years there will most likely not be many Altcoins to begin with
If someone can find a way to really tie in the coins together, I think that could help though. For example, allow people to buy services or items using *any* currency and have it automatically calculate the cost (I guess based on exchanges or something). I haven't fully thought through the idea yet but I am sure there are things people can come up with to help bring the coins, as a whole, closer together.
I do agree that it's going to be a long journey though!