What the article does not mention is that most of those networks are now gone. They started around 2000 as ad-hoc networks (a few friends that shared files through SMB and maybe an Internet connection) but around 2002 they evolved to be real businesses, with networks spanning tens of buildings and hundreds of apartments, sharing an expensive business link and even starting to do peering across networks. Most used copper cables across buildings, so they were quite often hit by lightning and network switches and cables had to be replaced (fiber was hard to install and maintain, as in some cases the physical security of the network equipment was low and media converters could be stolen).

Starting with 2005 the bigger/"normal" ISPs started to buy these networks (the businesses that maintained them), and migrate the customers to a more standardized / legal (and more expensive) network link.

Also, in the last years an underground fiber backbone was installed in Bucharest, and the fiber above ground started to migrate (not really willingly) to that. The problem is that there is no incentive to uninstall unused fiber from the poles (it's not valuable as a second-hand object and hard to recycle) so that fiber just stays there, in many cases broken.