The inclusion or omission of "it" changes the meaning drastically.
When modernization is achieved, the country as we know it will have dispappeared = When modernization is achieved, there will be nothing left of the country that we have now. The country will have been completely transformed.
..... the country, as we know, will have disappeared = People know that the country will have ceased to exist as a political entity.
The phrase 'as we know it' is fairly common. For example, there's a well-known song (I think it's by The Doors) with the chorus 'It's the end of the world as we know it'. I think it is usually used to talk about a major, often negative, change that's happening now or will happen very soon.
You can use it in the past tense as well:
'The world as we knew it in the 1920s and 30s no longer existed at the end of World War II.'
It can also be used to talk about a person:
'John, as we knew him, is gone. His body is alive, but I'm afraid he's permanently brain-dead.'
It's life, Jim, but not as we know it.
This famous one-liner from Star Trek is engraved in the brains of millions across the world. Of course Spock never said it (Check here for this and a few other mistaken quotations).
The difficulty for such people is that every time they come across the phrase "... as we know it ..." there is an immediate post-hypnotic response and they start prancing around chanting:
It's life, Jim, but not as we know it, not as we know it, not as we know it;
it's life, Jim, but not as we know it, not as we know it, Captain.
There's Klingons on the starboard bow, starboard bow, starboard bow;
there's Klingons on the starboard bow, starboard bow, Jim.
Errmmmm ... I think this post is in reply to
But is the structure < as we know it> a common one or rare one?