Not that surprising, really. The country's basically been in one state of war or another for the last 30+ years. It's not surprising that the infrastructure has suffered. Not to mention, much of that infrastructure was built by foreign powers as a means to curry favor and prevent (or help) the spread of Communism. Once that became less of an issue in the '90s, less and less money poured into the country. That, coupled with the foreign support of the mujahideen warlords (some of that came from the US) which eventually led to the ascension of the Taliban led to a pretty backwards period in Afghanistan.
That said, those pictures are basically '60s propaganda published by the government to show how modern the country was. Here are some other pictures from the same era, and I don't think things look all that different than how they do today:
http://www.pbase.com/qleap/afghan_1&page=all
Obviously some western influences have been stamped out, and it's really sad what's happened to the country; however, I don't buy the notion that it was some modern metropolis that has been destroyed. It's always been a very, very poor country and the problems due to regional and tribal differences as well as the divide between urban and rural areas have always existed.
What's truly sad isn't the fact that people don't dress like Westerners or buy modern furniture; but more how average people have been caught in the battle between competing, power hungry forces like the USSR/Russia, USA, Pakistan, Saudi Arabia, Iran, and the various warlord and tribal leaders within the country.